BMS News

It’s been a while since the last BMS Tropical Update on July 11. That update focused on Tropical Storm Barry, which eventually made landfall along the central Louisiana coastline as a minimal Category 1 hurricane. Even though it was a disheveled mess of a storm, it still caused nearly $100 million of insurance industry loss in Louisiana and set an Arkansas state rainfall record of 14.58” near Murfreesboro, Arkansas. Luckily, this large amount of rain did not fall along the Mississippi River in southern Louisiana, which was at already historic high levels along many sections, including levy-protected New Orleans. With Barry’s landfall, it joined 12 other July hurricane landfalls in the Gulf of Mexico since 1900. However, as we look forward to the remaining months of the hurricane season, it’s worth noting that there is no correlation between hurricane activity occurring before August and how much activity will be seen during the remainder of the season.

By now you may have seen the various updated Atlantic hurricane season forecasts, which, for the most part, continue to call for above-normal activity. As I have stated several times, the overall number is not what is important, but, rather, the steering currents that influence the track(s). Contrary to popular belief, however, most named storms have fairly regular and well-defined tracks because of the location and orientation of the Bermuda Azores high pressure, which ultimately determines the tracks of most named storms. The difficulty in predicting a storm track occurs either when the typical climatological steering wind flow is replaced by a less common, large-scale flow or, even more importantly, when rapid changes occur in the strength and orientation of the steering current, such as a bypassing mid-latitude trough, which is really only well-forecasted 5 to 7 days in advance.

The average date for the formation of the season’s third named storm is August 13, and the average date for the second hurricane is August 28, so there is nothing unusual about having a calm spell this time of year like we’ve seen recently. There have been several tropical waves that have propagated from the African coastline, and a few of these have been watched by the National Hurricane Center. Tropical Depression Three, which formed for less than 24 hours off of the eastern coast of Florida, provided a glimpse of where named storms could track this season if the current North American and Atlantic pressure patterns hold into the peak of the hurricane season. However, first let’s determine the factors to consider for the remainder of the hurricane season and then worry about the steering current once the storms begin to form. In the beginning of the season, it was suggested that named storms would form closer to the U.S. coastline rather than in the Main Development Region, and track closer to the eastern coast of the U.S. with the overall season seeing more back half activity.

Although many of the headlines suggest that an above-normal season is yet to come, these headlines should probably be taken with a grain of salt. Take the NOAA forecast, for example. There is a 45% probability of an above-normal season, which obviously means there is a greater chance of a normal to below-normal season at 55%. In fact, I don’t think there is much confidence in the August activity forecasts, even though they are usually the most accurate when it comes to the overall Atlantic Basin activity.

There are a number of reasons why there is a lack of confidence in the forecast:

• Lingering effects from El Niño, which is now in a neutral state. A neutral state El Niño should enable more activity across the basin, but sometimes the atmosphere has to play catch up to what is occurring with ocean temperatures half a world away which could still limit development this season.
• The Sea Surface Temperature (SST) pattern in the Main Development Region has been a little cooler than normal so far this season. However, SSTs are mostly above normal in the sub-tropics. While this isn’t typically associated with active seasons, it also means that tropical waves are more likely to further develop when they move out of the tropics and into the sub-tropics.
• It remains to be seen if the dry dusty air from the Saharan Air Layer (SAL) will weaken as typical climatology would suggest. But, there is no doubt that the presence of SAL has been one of the factors in limiting tropical convection so far this season.
• Another enabling factor has been the large-scale subsidence which has been over the Atlantic basin. Although the normal active MJO pulse has helped with bits of convection, the overall larger scale subsidence has been preventing large scale convection. The next MJO pulse could begin to influence the Atlantic Basin at the end of this month and then again in the middle of September.

Unfortunately, even with the more reliable August forecast, there are still a lot of variables for the remainder of the season. Perhaps the best guidance would be to view the analog years, which serve as a guide for potential activity and possible tracks for the remainder of the season.

This week we may see the remnants of an old stalled front off of the eastern coast of the U.S., providing a chance at tropical cyclogenesis closer to home. Hopefully, there won’t be a need for too many BMS Tropical Updates over the next 30 days, will be keeping an eye on how any potential events could impact the insurance industry.

Most Americans have fallen in love with the automobile, which is why miles of roadways reach across the country and so many residential structures in the U.S. have garages to keep these assets safe and clean. However, garages can become major problems in high wind events. When the doors to these large open spaces fail, it can cause major structural damage.
This past week, I was fortunate enough to attend the Insurance Institute for Business & Home Safety’s (IBHS) fourth Disaster Dynamics Academy session – Inside the Eye: Defending Homes Against Hurricane Damage. In this BMS Insight, I will share my experiences and what I learned about garage doors being a damage amplifier.

A Meteorologist’s Dream
Throughout my career, I have read countless papers about hurricanes, helped price and understand various aspects of hurricane risk, examined gigabytes of hurricane wind and claims data, and helped insurance companies recover after the devastation these events can cause. However, growing up and living as far away from an ocean as one can get, I’ve had limited firsthand experience with hurricanes. In fact, my only experience was on September 4, 2010, while living in Halifax, Nova Scotia, Canada, when Category 1 Hurricane Earl raced across the area. Most people wisely took shelter, but I took the more unconventional approach as a meteorologist to experience the hurricane-force winds for myself (as safely as possible). On that day, I headed out to Lawrencetown Coastal Heritage Park beach to experience my first hurricane. It truly gave me a new appreciation for what a hurricane can do and for what the insurance clients I support are facing every year.

Because I have spent most of my life living in the Upper Midwest, I’ve experienced my share of strong wind events while supporting insurance clients that have had to endure the same damaging windstorms. In fact, I’ve had firsthand experience with some of the research that the IBHS is currently conducting. I recently had a pole barn built on a big open farm field. On June 11, 2017, a strong line of thunderstorms worked their way across the western metro area of Minneapolis. A downburst of wind from these storms blew in the barn door, also causing damage to part of the roof. Luckily, there was no structural damage to the newly constructed barn, but, as a result, our replacement door was upgraded to a reinforced W4 door with a wind rating of 110 mph to prevent another similar incident.

Garage Doors Are a Wind Amplifier
During the Disaster Dynamics Academy, the IBHS showcased to its members the steps that can be taken to limit storm damage to various residential and commercial structures. After several years of IBHS demonstrations showing how fortified and non-fortified structures handle hurricane-force winds in its giant wind tunnel, this week they tested garage doors. After all, the garage door is a wind damage amplifier. Garage doors have a large surface area that can be affected by hurricanes and other severe convective winds events, such as downbursts or tornadoes. They are an amplifier because a breach often results in larger structural damage to the roof and walls. However, there are many questions about how this damage occurs, and the IBHS wind tunnel is the perfect place to find answers.
The IBHS conducts scientific research to improve building material performance and construction standards. Recent testing has included asphalt shingle performance research and continuous load path testing. The IBHS has also done extensive field investigation into past hurricanes and strong tornadoes, such as the 2013 Moore tornado, to help understand the various aspects of wind damage. One of the key findings from the garage door field investigation is that roughly 60% of homes had structural roof damage if the garage door was damaged, while roof damage hardly ever occurred if the garage door remained intact. This supports the notion that the garage door is an amplifier of damage.

IBHS Garage Door Testing
In the IBHS wind tunnel garage door testing, they were focused on determining the most appropriate methods and cost-effective practices to ensure that buildings are adequately constructed for the hazards they face. However, the questions around garage doors are complex. The internal pressure may be three times more than the external pressure, resulting in a large pressure difference between the inside and outside of the building. This can lead to major structural failure when the pressure equalizes. Damage that is commonly associated with a failed garage door is the collapse of an adjacent side wall. Some garage door failures may result in the loss of roof decking above the garage, or in extreme cases, the entire garage may collapse. If the garage door fails, it can also lead to a large amount of water entering the building, which can increase damage to contents from wind-driven rain.
The IBHS garage door testing looked at many different types of doors, including the double car door, single car door, twin single-car door, commercial roll-up doors, garage doors with and without automatic openers, and even insulated and non-insulated doors. There are many other variables that needed to be tested to help understand door failure, such as critical wind angles to the door and different wind speeds. The IBHS tested both wind rated doors and non-wind rated doors, as well as the types of hardware used to install the door. One could have a wind rated door, but it may come with normal hardware that could be prone to failure.

The Test
I can’t comment on all of the initial testing the IBHS has been conducting, but I can share my experience with the Disaster Dynamics Academy garage door test session. The test involved a normal big box store double garage door without an automatic opener. The standard two stall garage area was equipped with various pressure sensors along the wall and door; after all, the pressure on the walls is critical to what causes the overall failure. As the test began, the IBHS 105 Vaneaxial fan array, each with a 350 horsepower motor, were started at a steady 50 mph and were slowly ramped up every few seconds. As the fans approached hurricane-force levels, you could hear the wind whip around inside the six-story, 21,000 square foot testing area as turbulent winds began to flex the double garage door. As expected, the door folded in and hardware failed at around 90 mph. If it were not for the bracing behind the door to support the array of sensors, the door would have likely folded in completely and been ripped off its rollers and pushed to the back of the two stall garage space. Maybe the most exciting part of the test was the fact that the fortified structure sustained very little damage to category 3 winds, which was expected, as this was a test for doors and not to see the results of building failure. If the IBHS did a building failure test with every door, the testing could take years to complete, which is why the fortified construction is so important. Given the personal experience with my barn, and then seeing first-hand how easily a garage door can fail in the IBHS test facility, I believe there needs to be more attention paid to this wind damage amplifier. Currently, however, there are very few insurance companies that underwrite for such wind variables. What’s even more concerning is that very few areas of the country have building codes requiring wind-rated doors. Hopefully, with the important work that the IBHS is doing, the most appropriate methods and cost-effective practices for garage door construction can be determined. In addition, building codes could be established and existing code standards updated, all from using science in one of the coolest facilities I have ever been in.

As mentioned in the last BMS Tropical Update, a storm is brewing in the Gulf of Mexico.  The National Hurricane Center has now named this system Tropical Storm Barry and expects it to potentially become a hurricane by Saturday and make landfall shortly thereafter, with possible impacts along the coasts of Texas and Louisiana, particularly in the city of New Orleans.  As many already know, New Orleans sits below sea level and has had its share of flooding problems in the past.  Since water is the new wind risk for the insurance industry, this BMS Insight will focus on this threat in a bit more detail, as any wind damage at this time is uncertain given the high forecast uncertainty around the overall intensity and track of the storm.

The forecast models are suggesting as much as 18 inches of rain for the region, which isn’t good, considering that the area is already inundated with rain. New Orleans has already flooded this week from rain, with many streets covered with a dangerous amount of water.  The Mississippi River is expected to rise to 19 or 20 feet by the weekend, which is near the height of the city’s levees.

By Saturday, it may have winds of 85 mph, making it a Category 1 hurricane on the Saffir-Simpson wind scale.  It should be noted, however, that there is a lot of uncertainty around the forecasted intensity of the storm. This intensity will depend on how much wind shear the storm encounters and how much time it spends over the warm waters of the Gulf of Mexico.  Currently, the worst-case scenario appears to be a Category 1 hurricane.  However, forecasts can change fast, as we experienced with Michael last year.  Most of the model guidance is suggesting a lopsided tropical storm with a landfall somewhere along the Louisiana coastline.

Wind speed is just one of the insured loss concerns from the storm.  Historically, flooding has not been a big concern for the insurance industry, but the take-up rates of flood insurance are higher in Louisiana, including New Orleans.  The reinsurance markets are taking on some of the risk from the National Flood Insurance Program, so this flood risk needs to be watched.  Also, coastal flooding tends to be the deadliest aspect of a hurricane.

The main concern here is that the storm surge combined with heavy rainfall could reach 3 to 5 feet, which would flood many of the low-lying areas of Louisiana.  This storm is expected to generate a lot of rain, with some areas potentially seeing more than a foot, which can contribute to inland flooding along the banks of rivers.

The biggest threat from the storm may be in New Orleans, where the Mississippi River is already at 16 feet due to the very wet spring and summer upstream.  Some states along the river have seen their wettest spring in recorded history.  All of this water has worked its way down the Mississippi River, which has been high for well over a month now.  The National Weather Service is now predicting the river to crest at 19 feet on Saturday.  That is one foot below the top of the river levees. This could change given the track of the forecast. This morning the forecasted river height was 20 feet, so the forecast is changing for the better since the newest forecast is now one foot below the top of some of the levees.

So, why is this a concern?  During both Hurricane Katrina in 2005 and Hurricane Isaac in 2012, storm surge pushed well upriver. In those cases, however, the river was only at a level of 3 feet or less.  During Katrina, a Category 3 hurricane with top winds of 125 mph, the river swelled to at least 15.25 feet at the Carrollton Gage in New Orleans.  The gage stopped operating when the water reached that level.  Several barges were deposited on top of the levees in Plaquemines Parish during the storm by surge water.  During Isaac, a Category 1 hurricane with top winds of 80 mph, the river rose to 9.5 feet at the Carrollton Gage.  While the current river level in New Orleans is 16 feet, levees and floodwalls protect the city up to water heights of about 20 feet.

How high is a 20-foot-high river stage for New Orleans?  It is higher than 99.9% of the city’s land surface, higher than every human being except those in multi-story buildings and about 30 feet higher than the lowest neighborhoods.

In summary, the precursor for a bad flooding event is set for New Orleans and remains for much of the hurricane season.  Many areas of Louisiana are flat, and flooding is a big concern with this upcoming storm.  There is uncertainty at this time around the potential strength and track of the storm, which also increases the level of uncertainty around the storm surge that may be expected.  However, the rainfall forecasts have been fairly consistent over the last several days, with most of the heaviest rain expected to fall along with the storm’s forecasted path.

When Hurricane Michael made landfall on October 11th 2018, it had a central pressure of 919mb, which is the third lowest pressure of any U.S. landfalling hurricane. Yet, at the time, the storm was classified on the Saffir Simpson Hurricane Scale as a Category 4 hurricane with winds of 155 mph – only one mph below the Category 5 criteria. On April 19, the National Hurricane Center (NHC) announced what some meteorologists were already thinking, that, at the time of landfall, Hurricane Michael was actually a Category 5 storm with a wind speed intensity of 160 mph. The NHC bumped up the maximum wind speed based on a detailed analysis of aircraft, Doppler radar velocities, and new surface wind speed observations. It is worth noting the caveat from the NHC report that the maximum winds were in a very small area and future revisions are possible. Reconstruction of Stepped Frequency Microwave Radiometer (SFMR) winds showed possible higher values, but the reliability is still unknown, and more research is being done on this data.

There is also some other useful information to the insurance industry in the NHC report. Along a wealth of observational data the report also details some important loss information. The National Centers for Environmental Information (NCEI) currently estimates total economic damages from Michael in the United States at $25B. There have been several media articles written about the continuing insurance loss development. With a current insurance industry loss at $10B, the overall figure is coming close to the generally-held rule that the economic loss is about half the insured loss for U.S. landfalling named storms. Another interesting aspect of the report is the overall damage figures. For example, $3B of loss was on Tyndall Air Force Base near the landfall location. The damage survey suggested that every building at the Base was damaged to some degree. In Mexico Beach, 1,584 out of the 1,692 buildings were damaged with 48% being completely destroyed. The report also goes into damage figure details for Bay County and Gulf County. For example, Marianna, Florida, which is over 50 miles inland, had 1,000 buildings destroyed or with major damage. Seminole County in the Southwest part of Georgia reported 99% of homes were damaged from wind gusts in excess of 100 mph.

Not to be overshadowed, the storm surge section of the report is just as impressive. The storm surge surveys and analysis revealed maximum inundation of 14.7 feet above what is normally dry ground in Mexico Beach, which would also explain much of the damage found in that area.

The formality of upgrading Michael from a Category 4 to a Category 5 is a big deal. Michael is now tied with the San Felipe Hurricane of 1928 or also known as Okeechobee hurricane as the fourth strongest hurricane to strike the United States (including Puerto Rico) since 1900, behind the Labor Day Hurricane (1935), Camille (1969), and Andrew (1992).
If you believe empirical landfall probabilities, the addition of Michael in the U.S. record since 1900 has increased the probability of a Category 5 storm making landfall from 2.52% to 3.36% or, in terms of a return period, 40 years to 30 years. As respects Florida only, the same calculations went from 1.68% to 2.52% and 60 years to 40 years.

Constantly Changing View of Landfalling Hurricane Risk
So, has the overall risk for the insurance industry increased? How will this new data change the insurance industry’s view of landfalling frequency and severity?

Hurricane risk across the U.S. is understood through the use of catastrophe risk models that employ stochastic catalogs containing thousands of events, each one with a small impact on model results. There is an ongoing process of recalibration of the stochastic catalogs. This constant reevaluation of current and past storms contributes materially to the development of a rich stochastic set of events informed by the historical record that is adjusted based on history or future forecasts.

Due to advanced observation techniques and improved understanding of tropical cyclones, the Hurricane Research Division (HRD) has implemented a data set (HURDAT2) that addresses errors and biases identified in the historical record. A working group of scientists makes corrections to location and intensity information in the six-hour track points for select tropical cyclones. Additionally, this research, supported by new evidence and data, adds previously undocumented cyclones to the record. Currently, the scientists are looking at storms after 1960 with further changes likely as a result of new findings.

One does not need to look very hard for proof that catastrophe modeling companies use changes in HURDAT2 to help adjust landfall frequencies. Recently, HURDAT2 updated Hurricane King (1950) from a Category 2 to a Category 3 storm resulting in a long-term rate increase in Miami Dade County in one of the stochastic catalogs. Another notable example of a tropical cyclone reanalysis is the Labor Day Hurricane of 1935. Upon reanalysis, the maximum wind speed at the time of its first landfall over the Florida Keys was increased (23 mph), increasing its intensity to strong Category 5 status. This reanalysis revised the Labor Day Hurricane to be the strongest U.S. landfalling hurricane in the historical record. Additional reanalysis upgraded its second landfall, in northern Florida, from Category 1 to Category 2 intensity and shifted its track closer to land. This change also resulted in changes in loss results from the Florida region in particularly using this event as a historical what if scenario.

As Hurricane Michael continues to be examined by researchers, recent activity will also adjust landfall rates. In fact, the most recent updates of HURDAT2 reevaluated landfalling events during the 2015 – 2016 season, including Hurricane Hermine (2016) and Hurricane Matthew (2016), yielding localized loss increases in the landfall areas. Similarly, losses increased in Canada due to changes in landfall categories for some storms during the 1956 – 1960 period as part of the HURDAT2 updates. In areas that didn’t see any new landfalling storms, small decreases in loss across mainland U.S. resulted.

With the knowledge that Hurricane Michael is, in fact, the fourth Category 5 hurricane to make landfall along the U.S. coastline, it will surely change the historical view of risk, particularly in the Eastern Florida Panhandle, which already has a limited historical record of major hurricanes making landfall. Michael is now the strongest hurricane landfall of record in the Florida Panhandle and only the second known Category 5 landfall on the northern Gulf Coast. Additionally, Michael marks the latest in the season a Category 5 hurricane has made landfall in the United States. All of this should be factored into new landfall rate adjustments.

It is too early to determine potential changes to future stochastic catalogs, but these revisions tend to be in the single percentages based previous Atlantic Hurricane model updates. It should also be a reminder, however, that just because the landfall frequency and severity might change for major hurricanes, the insurance industry should not forget storms of lesser intensity can also cause billions of dollars in loss. Any hurricane can cause great devastation.

The Season Has Begun
There has undoubtedly been a lot of attention given to severe weather across much of the U.S. since the end of April, but in the meantime, the Atlantic hurricane season has arrived. In fact, most people may not have noticed that the Atlantic Basin already had its first named storm (Andrea) of the season. Andrea was a short-lived (less than 24 hours) storm that formed on May 20, about 300 miles south of Bermuda. Andrea became the fifth tropical storm to form before the official start of the Atlantic hurricane season, which did not officially begin until June 1.

Dates of first named storm formation over the past 50 years. The official start of hurricane season is marked by the horizontal green line, and the median date of the first formation is marked by the horizontal dashed black line. The trend over the past 50 years has been for the first named storm to form earlier, with a large spread. There is no correlation between an early start of the season and the season’s overall activity, as discussed here. Source: (Brian McNoldy)

According to the National Hurricane Center, there is a 60% chance of named storm development in the near term in the southern Gulf of Mexico. It’s typical for us to see early season development in this area. At this time, most of the forecast models are bringing tropical weather up into Texas, which will also bring more moisture to the Central Plains where it is surely not needed at this time.

Invest 91 is a tropical disturbance in the southern Gulf of Mexico, which could develop into a named storm as it moves northwest over the coming days. Source: Weathermodels.com

Seasonal Forecasts

I was recently asked: “Does the insurance industry place any weight on seasonal hurricane forecasts?” My quick answer was Yes and No, as it depends.

To elaborate on the Yes part: The insurance industry has always been supportive of seasonal hurricane forecasts by subscribing to private forecasting companies and by funding academic research in these areas. Most companies don’t like surprises and, naturally, being prepared is the logical thing to do for both the reinsurance and insurance industries. However, insurance companies may be more limited in what they can do than reinsurance companies.

The seasonal forecasts can influence the strategic planning of an insurance company by making sure they have adequate claims adjusters in place going into the hurricane season to better serve their customers. Of course, an active hurricane season might require an insurance company to consider service level agreements or loss adjustment expenses and the effects of demand surge that might need to be paid in an active hurricane season. However, since the insurance industry is heavily regulated, companies have little ability to adjust rates for an active or inactive season ahead of time. The reinsurance industry, on the other hand, can be a bit more opportunistic when dealing with seasonal forecasts in terms of planning ahead to provide reinsurance in the secondary market.

To the No side of the answer: Capital requirements for insurance companies are regulated by rating agencies and the insurance commissioners of each state, and do not allow for rate adjustments on a seasonal basis. As part of its strategic planning, an insurance company may want to stress test a portfolio to a certain loss level, as it has the ability to buy more reinsurance during the season if it is uncomfortable with the potential losses that may come from a particular seasonal forecast. The extent of just how much seasonal forecasting plays into each insurance company’s strategic planning is unknown, but generally, insurance companies spend considerable time with strategic planning to understand the potential of losses in any given season, regardless of the Atlantic Basin seasonal activity.

From a business perspective, it’s hard to rely heavily on forecasting when the accuracy of seasonal forecasting is low. Historically, in June seasonal forecasts, the forecasting of activity has not correlated well with actual insurance industry losses. How many times have you heard about 1992’s Hurricane Andrew and how that season was a below normal year? Yet, Andrew happened and was a very big loss for the industry. “It only takes one” will haunt the industry until forecasting gets better.

The readers of my past Atlantic hurricane seasonal forecasts may know that I am all for our industry moving away from simply looking at activity in terms of the number of named storms and hurricanes the Atlantic basin might produce, and rather focus more on what the pattern is suggesting in terms of landfall impacts. This is where we will find the most value, as I describe in more detail below.

Seasonal Forecast and Landfall Threats
The seasonal forecasts we see each year from various sources that provide a number range of expected named storms and hurricanes in the Atlantic Basin are a dime a dozen. There is usually a considerable spread in these forecasts. Currently, there are 19 different forecast groups that have submitted Atlantic seasonal hurricane forecasts to http://seasonalhurricanepredictions.bsc.es/ . The average of these forecasts calls for 6 hurricanes, which is closer to an above normal season.

What do El Niño and La Niña have to do with tropical cyclones? During El Niño, wind shear increases in the Atlantic and we see cooler sea surface temperatures. In La Niña, wind shear decreases and the sea surface temperatures become warmer in the Atlantic, fueling more tropical cyclone activity. Source: NOAACliamte.gov

One of the major factors being considered in many of these forecasts is what the state of El Niño Southern Oscillation (ENSO) may be during the hurricane season. Currently, there is a weak El Niño occurring in the tropical Pacific, and this is forecasted to maintain into the heart of hurricane season. El Niño historically limits named storm development by increasing wind shear across the Caribbean and the Main Development Region. However, not all El Niños are the same, and this El Niño is a Modoki El Niño. This means that the warmest water is found in the central Pacific rather than off the coast of South America. We may see less of an overall impact on Atlantic hurricane season activity with a Modoki El Niño.

General difference between La Niña and  El Niño season.  However, the current El Niño is more of a Modoki El Niño which has less overall impact on the Atlantic hurricane season. Source: NOAA

Another factor to consider, which I think some of the seasonal forecasts may be missing, is that the depth of warm water is shallow and there is actually cooler than normal water beginning to show up at depth, which actually suggests more of a La Niña signature. This could mean that we see very little El Niño impact this hurricane season and instead begin more of a transition to a La Niña weather pattern for 2020.

The image to the left is the  vertical profile of the water temperatures at depth across the Pacific Ocean from South America to Australia as represented by the black line in the image to the right. Note the cold water below the warmer sea surface temperature closer to South American coastline with much of the warmer than normal water in the Central Pacific, which is more of a classic Modoki El Niño signature. Source. NOAA CPC

Sea Surface Temperatures across the Atlantic are currently warmer than usual, which would suggest a more active season. However, we may also want to consider one of the indexes that the insurance industry has looked at for over two decades now. According to Colorado State University, the Atlantic Multidecadal Oscillation (AMO) is currently in a cold phase, which historically would limit named storm activity in a given season, however, SST will be plenty warm enough for named storm development.

The other two factors to watch this Atlantic hurricane season will be Saharan dust and the Madden Julian Oscillation (MJO). Both of these are difficult to predict at seasonal time scales, but understanding the phases of the MJO can help determine when named storm development will occur. The MJO is the major fluctuation in tropical weather on weekly to monthly timescales that comes from pulses of tropical convection over the subcontinent of Asia. The MJO can be characterized as an eastward moving ‘pulse’ of cloud and rainfall near the equator that typically recurs every 30 to 60 day. In fact, the Atlantic basin is currently going into a phase (The MJO is currently in phase 3 and about to enter phase 4) that is not conducive to tropical development. It would appear unlikely that anything of substance develops in the Atlantic Ocean through early July as El Niño and the phase of the MJO limit convection development, which would also limit named storm development.

Overall, it looks like we have the potential for another late blooming season for 2019 with some subtropical development between now and the middle of July, along with a chance for a weak named storm in the Gulf of Mexico this week.

Saharan dust can be an inhibitor of Atlantic Hurricane activity, but it often moves off Africa in waves. In between these breaks of dust, and when combined with the right phase of the MJO, you can find that named storm development has a higher probability of occurring.

Above are the phases of the MJO and the tropical storm tracks that have occurred across the world. Atlantic Ocean is to the far right in the images above.   The MJO can also considerably influence hurricanes in the Gulf of Mexico, Caribbean Sea, and tropical Atlantic. More hurricanes tend to occur in MJO phases 2 and 3 than in phases 6 and 7. Differences in major hurricane numbers and hurricane days in the main development region are a factor of 3. Source: https://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-12-00026.1

As we’ve discussed, there are multiple factors to weigh when trying to predict the timing for named storm development. However, what are the seasonal climate models suggesting in terms of the possible tracks for named storms? As seasonal climate models continue to get better, we can begin to pick up on the overall pressure and precipitation patterns to help determine where storms will track.

The ECMWF Climate model is suggesting higher wind shear across the Caribbean which would limit tropical storm development in this area.  However, a window of lower shear is forecasted for the Atlantic hurricane season from the Bahamas to south of Bermuda.  Source: Ben Noll Weather

The CanSIPS  climate forecast model provides an view of where the Bermuda Azores high might be positioned for the Atlantic hurricane season. The lower than normal pressure coming from the model could suggest area of more named storms. Pressure below average near U.S. coast, above average in Main Development Region. Source: TropicalTidbits.com

Seasonal climate models are suggesting that above normal precipitation will be occurring this summer off the eastern coast of the U.S. This suggests that this is where the storm track may set up for the season, as storms bring above average rainfall to the eastern coast of the U.S. and the island of Bermuda. Also notice less overall rainfall in the central Atlantic suggesting storms might form closer to the East Coast if they develop. Source: Ben Noll Weather

Summary

I am expecting a more active than normal (Named Storm and Hurricane Storm Counts) Atlantic hurricane season as I think the Modoki El Niño will have less of an overall impact. When one combines this with the warmer than normal SST and weaker than normal wind shear near the East Coast, the conditions should allow for more than normal named storm development. The climate models are suggesting above normal precipitation on the periphery of the west side of the Bermuda high, which could come in the form of named storms during the summer months.  The key to the overall season will be how the MJO and Saharan dust enhance convection, with the next best possible window after this week coming in early July.  How all of this insight will impact the insurance industry is a big question at this point in time, but risks along the East Coast need to be watched.

Catastrophic weather events in 2017 left the re/insurance business with a conundrum. Record-breaking insured catastrophe losses exceeded any previous year. However, the impact of those unprecedented losses on re/insurance pricing has been less than many had hoped for or expected. Claims of nearly $140 billion have not delivered a traditional hard market.

To solve the conundrum and learn the year’s lessons, we must view the storms, fires, and floods of 2017 in a long-term historical perspective. We should not use loss data alone to define weather and climate trends; we need to also understand the impact of the growth of global wealth, as well as patterns of weather extremes.

When we do so, we find that the record-breaking losses were not so enormous, and could have been worse.  About $92 billion of 2017’s insured catastrophe losses arose from three major hurricanes according to the latest Swiss Re Sigma Report. When indexed to 2017 values, Hurricanes Katrina, Rita, and Wilma in 2005 caused insured losses of $112 billion.

We also need to consider that extreme weather memories are typically short. Catastrophe models that simulate the impact of historic storms in today’s built-up environments show that  events such as 1926’s Miami Hurricane or the 1928 Okeechobee Hurricane would cause insured losses that surpass those of 2005 and 2017 hurricane losses. When other named storms and natural catastrophes that occurred worldwide during those years are included, the insured impact on our modern built environment would easily exceeds $140 billion.

Bay Shore Drive in Miami then 1926 after Hurricane and Now. Source NOAA and Google Street View

Meanwhile there is a perception that extreme weather patterns may be changing.  In some cases the data supports this perception.  It is likely that, since 1951, the number of statistically significant regional increases in heavy precipitation events is greater than the number of declines. Strong regional and sub-regional variations modify the trend, but in short, when it rains it often rains more. However, despite the increase in these extreme precipitation events, little evidence suggests the rainwater has led to an increase in floods, with lots of regional variations.

The U.S. Climate Extreme Index quantifies the observed changes in one-day precipitation extremes across the U.S. Since 1990, there has been an increase in the area of the U.S. that has experienced a one-day extreme rainfall.

Tropical cyclones seem not to be changing. After accounting for past shifts in observational capabilities over time, the best records that started in the 1970’s suggest, globally, there are currently no significant observed trends in the number of named tropical cyclones, but the data is suggesting that, when named storms form, they have become stronger in recent years.

2017 had 18 total landfalling named storms. 14 of these had a category 1 or 2 and four of the three major categories were in North America.

As for severe weather, poor data quality makes conclusions about long-term trends problematic. Observed trends in small spatial-scale phenomena such as tornadoes and hail can be made with only low confidence levels, but more recently the data is suggesting clearly a downward trend in the number of occurrences of major tornadoes.

A lot of talk today about the anniversary of the April 2011 Super outbreak. With Joplin later next month many said after 2011 we would see more frequent major tornadoes. Here is the trend which shows a noticeable downward trend since 2011. #MajorTornadoDrought pic.twitter.com/HD3idKeAYI

— Andrew Siffert (@AndrewSiffert) April 27, 2018

With all this in mind, we should learn lessons from the 2017 experience.

• Whether it was the major wildfires in California, flooding of Harvey, the extreme winds of Irma over south Florida, or one of the many damaging hail storms; exposure management is very important and there needs to be a refocus on this simple task to limit losses.
• Valuable data will be collected from the 2017 events, especially from the high wind speeds from HIM. This data will fill critical gaps in the historical record and will be valuable both meteorologically and financially, as it will help insurers and customers by providing better loss models, and lessons for loss mitigation and resilience.
• Building codes matter. When wind-speed data is combined with claims data, we get critical knowledge of how high winds damage different types of construction. We now have validation for some wind-tunnel testing which has been lacking due to the lack of hurricane landfalls over the last decade.
• Hurricane forecast track and intensity still have a great deal of uncertainty. The 2017 landfalls raised questions about the value of early landfall loss projections, and how they could be used.
• Effectively, the people who need flood insurance do not have it.  How many more flood events like Harvey and Katrina do we need before more action is taken?
• Companies with the best business interruption (BI) insurance came out on top after an event, but few small businesses don’t have enough BI.
• Demand for certain post-event services seriously tested supply. The lack of adjusters, for example, created a major bottleneck that led to very high loss adjustment expenses.
• Given the long 10 years without major hurricane landfalling activity, 2017 was a great systems test for InsurTech.  It would appear no major lapses in these new technologies have occurred which should further expedite system enhancements in InsurTech.

You might have noticed that the first named storm (Arlene) of the 2017 Atlantic Hurricane season has formed in the middle of the North Atlantic Ocean – 815 miles west of the Azores Islands.   The biggest impact from this storm will be the discussion in the meteorology community as to whether this system should even be monitored by the National Hurricane Center.  Currently Arlene is over relatively cold ocean water (66 F (19 C)) for a tropical system, and according to satellite data, it is questionable if the system has a warm core.

IR Satellite image show the system is over 19C water.

Typically a tropical cyclone is characterized by lack of warm/cold fronts attached, a “warm core” (air is warmer in center of the cyclone than elsewhere), and persistent deep convection wrapped close to the center; these attributes are commonly referred to as “tropical characteristics” of a cyclone.

It would appear that the decision to track Arlene is very subjective: there have likely been dozens of similar systems over the last 100 years (systems that develop in water warmer than 66 F and with a marginally warm core) that have gone unclassified, including systems that have impacted the U.S. (Sept 2008 SC coast, Sept 2009 NJ).

All this matters to the insurance industry because our hurricane catalogs in the catastrophe models are tuned to the historical data, and after decades there is still no objective guidance as to what type of system gets tracked by the NHC. In some cases like Sandy, questionably categorized storms can have large impacts on landfall definitions as well.

Regardless, Arlene is now in our record books as a storm in the North Atlantic, but it will not be around for long as a strong mid-latitude trough will merge with this system later this weekend and make it unrecognizable. These early-season tropical systems should be no surprise (this will be the sixth early-season storm in the past six years). In fact, history suggests that tropical/subtropical systems in April are uncommon, but not necessarily rare. There have been a few, but they are typically short-lived and innocuous.

Historical Storms that have occurred in April

I am currently tracking the various early season forecasts for the 2017 Atlantic basin season.  I should have my views formulated in a couple of weeks.  What I can tell you right now there is no correlation for April storms and the rest of the season, partly because of a small sample size.

Three weeks ago, James Kossin published a major study in the scientific journal Nature: “Hurricane intensification along United States coast suppressed during active hurricane periods” (http://www.nature.com/nature/journal/v541/n7637/full/nature20783.html). This paper has gotten a bit of press in various insurer publications as over the last decade near term hurricane risk has dramatically influenced the insurance industry in hurricane-prone states. In short, Kossin’s paper provides valuable insight into rapid hurricane intensification during active and inactive periods of hurricane activity in the Atlantic basin (known as the warm and cold phase of the Atlantic Multi-Decadal Oscillation [AMO]). The findings suggest that approaching hurricanes are more likely to intensify before landfall during colder phases of the AMO and are more likely to weaken before landfall during warmer phases. Suggesting that during times when the sea surface temperatures are anomalously warm in the main development region, regions along the U.S. coast experience higher then normal vertical wind shear. Furthermore, the local sea surface temperatures are substantially cooler than the main development region which tend to inhibit intensification and form a “protective barrier” along the United States coastline during this period.

My very first thought as I read about this “protective barrier” was, finally, someone has scientifically proven the existence of HAARP and electromagnetic capabilities of the ionosphere that conspiracy theories suggest can also be used in weather modification and more. (i.e., a “protective barrier” created to control the weather (hurricane landfall))! (If you’re unfamiliar with the HAARP conspiracy theories that abound, then you won’t get this reference, but it’s one of the top questions meteorologists get asked, and you can learn more at http://www.nbcnews.com/science/weird-science/conspiracy-theories-abound-u-s-military-closes-haarp-n112576.)

How the Science has Changed

In all seriousness, to truly understand the impact of Kossin’s paper, it’s important to review how our understanding of active and inactive phases of the Atlantic Ocean has evolved and influenced the insurance industry. Since the 1960’s, the late Dr. Gray showed distinctly differing environmental conditions for tropical cyclone development. But not until the marked increase beginning in 1995 did insurers begin to notice what drives this activity. After the costly 2004 and 2005 hurricane seasons, a dozen and half papers highlighted a link to increased hurricane activity due to a warming world and/or the current phase of the AMO. About the same time, catastrophe modeling companies were being pressured to adjust for this increased frequency and severity that had impacted the insurance industry since 1995. Modeling companies incorporated a range of statistical analyses, and in some cases expert elicitation, to make assessment on future hurricane landfalling risk.

Mother Nature, however, does not always follow weather trends; and since 2005, the U.S. has entered what some have called a “U.S. landfall hurricane drought.” While overall named storm activity remains elevated across the Atlantic basin with some very active years since 2005 (2010, for example), many hurricanes have not made landfall as expected, which is actually influencing the long term landfall rates across the U.S. A few recent research papers suggest that scientists never settled on the exact impact the warmer phase of the AMO might have had on U.S. landfalls. Some of these papers suggest that in a warmer world, African dust and/or North Atlantic sea surface temperatures could actually encourage hurricanes to form further east or recurve before impacting North America, resulting in a lower U.S. hurricane landfall rate.

But Kossin’s paper provides new evidence that the science is not settled, and there is a lot to learn about hurricanes and the rate at which they make landfall. In general, the correlation between the number of hurricanes that develop in the Atlantic basin and number of hurricanes that make landfall is weak. This new study in Nature could explain part of this relationship as it highlights that elevated wind shear (changing wind speeds with height) and cooler sea-surface temperatures along the U.S. coast during the warm active phase of the AMO create conditions that tend to weaken hurricanes as they approach the U.S. coast. Conversely, the cool phase of the AMO makes approaching hurricanes more likely to intensify. This might conflict with ideas that some scientists suggested prior to 2004 and 2005, that the warmer phase of the AMO was correlated to more landfalls and possibly stronger landfalling storms (and fewer landfalls during the cooler phase of the AMO).

The Hurricane “Drought” can be Explained

Kossin suggests in his paper’s closing that this new research could possibly explain the recent “drought” of major hurricane landfalls. However, in late 2015 another research paper funded by Risk Prediction Initiative (“The Arbitrary Definition of the current Atlantic Major Hurricane Landfall Drought”) suggested the major hurricane drought is more a function of the definition of a major hurricane (defined as a Category 3 or higher on the Saffir-Simpson Scale) and the uncertainty in wind estimates. As an example, Ike (2008) made landfall as a high-end Category 2, but could just as easily have been classified as a low-end Category 3 at landfall. For contrast, consider a storm like Sandy (2012), which was not even classified as a hurricane at landfall, but still resulted in large wind and storm surge insurance losses.

Image created by Roger Pielke Jr. who has been keeping track of the days between major hurricane landfalls.

It’s important to remember that only 78 major hurricanes have made landfall since 1900 (117 years), which results in a particularly small sample size, and that there are likely many other factors that affect intensification before landfall. Hurricanes can experience higher levels of disruptive wind shear while turning north, which could be due to a large scale trough of low pressure or drawing in dry air from landmasses. Hurricanes can also send large waves and surge ahead of the storm causing warm water to mix with cooler water and deplete important energy from the storm as it approaches land. These vacillating factors highlight the complex interactions hurricanes may experience during a life cycle. These factors could also explain why many hurricanes have not intensified prior to U.S. landfall (with the exception of Charley [2004] and Humberto [2007]).

Future Hurricane Landfall Rate Models

As always, new research will continue to become available and catastrophe modeling companies will continue to judge how the science best fits into catastrophe models. This new research should not discredit near term view modeling work. Hindsight is 20/20, and as Hall, T.M., and K. Hereid, 2015: The frequency and duration of U.S. hurricane droughts paper suggests several observations point to the current drought being more a case of good luck than any shift in hurricane climate. Therefore this luck could have swayed higher then normal insured losses in a completely different direction over the last 10 years. These facts highlight why it is important to continuously evaluate new science. Modeling companies need to ensure they avoid knee-jerk reactions to industry demands or speculative science. Seasonal hurricane forecasts are improving, and with time, multidecadal sea surface patterns and other variables could help clarify the cause of reduced landfall rates, not just in the Atlantic basin, but in other basins near high exposure. El Niño/Southern Oscillation (“ENSO”) and other variables could also be worked into the landfall rate catalogs produced by model vendors.

As pointed out in this blog, the science might not be settled on hurricane landfall rates and what drives these rates during particular climatic conditions. Although it is short by climate standards, the U.S. landfall hurricane record is one of the best natural catastrophe databases insurers have to understand frequency and severity. There is a reason why catastrophe model companies calibrate their models to the longest period of record available.

There is plenty of room for debate about near term hurricane landfall rate models, the drivers of this risk, and what position an insurer should take regarding rate models. Are they a good idea or a bad idea? Should a blended approach be used? Those are interesting questions and a worthy topic, which is why I will be moderating the session, “Is Near Term vs. Long Term View of Hurricane Risk Over?” at the February RAA Cat Management Conference. We hope this subject generates lively discussion and hope to see you there!

Now that Matthew’s story is complete, immediate attention will turn to Nicole, a tropical storm currently 450 miles south of Bermuda. The models generally agree that Nicole will slowly strengthen back into a hurricane and that there is a good chance that Matthew will become a strong category 1 or weak category 2 hurricane as it tracks close to Bermuda this Thursday.
So with no tropical troubles threatening the U.S. coastline in the immediate future, this is the time of year that the insurance industry often wonders if there is any other tropical trouble forecasted for the remainder of the year.

Climatologically over the next two weeks we tend to see stable named storm activity, but after October 18th, the activity in the Atlantic Basin drastically trails off.

This is also roughly the time of year that the West African – Cape Verde type hurricane season trails off due to the equator-ward shift of the African Monsoon. This past weekend the overall tropical rainfall seemed to shift below 10 degrees north latitude, which is the benchmark for tropical waves coming off Africa to obtain enough spin to become named storms.

Here is a look at the tropical rainfall totals since mid July. It shows the height of the African Waves during middle of August with a trailing off over since this period. The axis to the left is latitude showing a trend towards the equator.

This is also the time of year that colder Canadian troughs of low pressure air start to invade the U.S. Often these weather systems leave trailing cold fronts that sometimes extend into the southern Gulf of Mexico or Caribbean. Low pressure can form at the tail end of these fronts, and if the water is warm enough in the Gulf or Caribbean, it can encourage tropical convection which could then become organized. These typical developments are consistent with some of the models’ long-range weather forecasts for later next week.

Forecasts for Thursday morning show an area of low pressure moving across the upper Great Lakes, which could provide the first freeze of the year for the upper Midwest. This forecast also shows Nicole moving toward Bermuda.

This low pressure moves across the north Atlantic late next week, and it leaves a trailing cold front with an area of low pressure off the east coast of Mexico in the western Caribbean. This is the area that needs to be watched for tropical trouble later next week as the water in this area is plenty warm enough to support tropical convection.

The long range forecast from Oct 17  – Oct 24th  total precipitation plot below show a decent amount of rain which could be  from  convection thunderstorms.

The graphic below illustrates the climatological pattern that is typical of tropical storms that originate in October so the Western Caribbean is the place to watch over the next three week.

Mathew End Game

Matthew is now classified as a post tropical storm as the majority of its energy has merged with a mid-latitude frontal system.   As a result Matthew will once again defy the long range forecast models that had suggested Matthew’s energy would travel southward towards the Bahamas.  Now Matthew will go out to sea just like the majority of tropical systems and Matthew’s long story will end.

Matthew Forecast issued at 8 am EDT Saturday Morning. Showed Matthew likely taking a southern track in the long term

Almost a complete 180 degree change in the direction Matthew is expected to take in today’s 8 AM NHC official forecast. Now Matthew is expected to track north of Bermuda.

Flooding

However, the damage is done and it is becoming apparent that water related damages could add up to more than the wind related damages.   In fact’ the water damages will continue to add up as many major rivers in Carolinas are expected to hit record flood levels.  In some cases there have been dam breaks which is reminiscent of the incredible rain event just over a year ago from tropical moisture from Hurricane Joaquin.  So with major rivers still rising, the flood situation is still unfolding, particularly in North Carolina which will lead to more losses in the next few days. However, it is assumed the majority of the inland flooding / river/ storm surge losses are either uninsured or are being assigned to flood policies by the NFIP.   As shown yesterday, the National Flood Insurance Program take-up rate by counties which are heavily coastal in nature across northern Florida through the Carolinas decreases for inland counties.  Therefore the majority of insured losses should be driven by wind related claims.

Record flooding forecasted at Goldsboro, NC

Record Flooding forecated for Kinston, NC

This record river flooding is a result of heavy rainfall which in some places has totaled more than 12”

Past 7 Days of Rainfall observed. It should be noted BMS iVision also has a rainfall layer users can use to understand risk impacts to flooding.

As highlighted in yesterday’s update storm surge has also done a lot of damage along the entire coast from Flroida up to North Carolina.

• Mayport, FL 3.28 feet:  Previous record of 2.47’, during Hurricane Jeanne on September 27, 2004 (records since 1928.)
• Fort Pulaski, Georgia 5.06 feet:  Previous record of 3.40’ during the October 15, 1947 hurricane (records since 1935.)
• Wilmington, NC 8.21 feet:  Previous record of 8.15 feet during Hurricane Hazel in October 1954.

Vilano Beach homes, and what’s left of the dunes they were built on @FCN2go#FCNStormpic.twitter.com/MXhUjIF6ss

— anne schindler (@schindy) October 8, 2016

Notice in the image above however that one of the areas hardest hit by winds in Florida right along the coastline. Most of the homes are relatively undamaged from this view.   Other damage from University Florida Damage Assessment group find minor roof and exterior damage along parts of the Florida coastline with surge leading to most of the damage observed.

Wind damage

As pointed out several days ago, treefall would be enhanced due to the saturated soil conditions in the Carolinas. With this combined with wind gusts and the lack of any significant large scale wind event over the region in several years, wind related tree damage could increase insured losses.

Since wind related damages will likely drive the insured loss, users of BMS iVision can now get a full picture of Matthew’s wind swath by looking at the 1 minute wind speed and 3 sec gust wind speed.   In the coming days   users will find wind duration information.

BMS iVision Verisk Climate 3 sec wind gust swath for Matthew

Industry Loss

The only public report of insurance industry loss numbers was in a report issued Saturday afternoon by, CoreLogic, which estimates Matthew’s insured losses to range between $4B to $8B with 90% of loss being driven by wind claims, 10% by storm surge.  These estimates are well below the industry loss estimates projected by the major catastrophe modeling firms late last week.  However, they are somewhat inline with the other industry loss numbers from other modeling firms (not yet released publicly).

While Matthew was within 20 miles of bringing much larger insured property losses, Phil Klotzbach of Colorado State has compiled the historic statistics on Hurricane Matthew.

Hurricane Matthew Records/Notable Facts Recap (through October 8)

Intensity

• 80 mph intensification in 24 hours – the 3rd strongest rapid intensification in the Atlantic on record (trailing Wilma-2005 & Felix-2007).
• 31st Atlantic Category 5 hurricane on record and the 1st since Hurricane Felix (2007)
• Lowest latitude Atlantic Category 5 hurricane on record
• 6th lowest MSLP for any Atlantic October on record at 934 mb (trailing Joan, Opal, Mitch, Wilma & Joaquin). Consistent MLSP records date back to 1979.

Longevity

• Longest-lived Category 4-5 hurricane in the eastern Caribbean (<=20°N, 90- 60°W) on record.
• Generated the most Accumulated Cyclone Energy on record for any hurricane in the eastern Caribbean
• Maintained Category 4-5 hurricane strength for 102 hours in October – the longest that a hurricane has maintained Category 4-5 strength on record during October in the Atlantic
• Maintained major hurricane strength for 7.25 days – the longest-lived major hurricane forming after September 25 on record and longest lasting at any time of year since Ivan (2004). Tied with Fabian (2003) for 5th longest major hurricane in satellite era (since 1966)
• Currently ranked 8th for Accumulated Cyclone Energy by an Atlantic hurricane in the satellite era

Landfall

• 1st Category 4 hurricane to make landfall in Haiti since Cleo (1964) – 1st Category 4 hurricane to make landfall in Cuba since Ike (2008)
• 1st time on record that a major hurricane has made landfall in Haiti, Cuba and the Bahamas
• 2nd time that a Category 4 hurricane has made landfall in the Bahamas since 1866 (Joaquin-2015 was the other)
• 1st hurricane to make landfall in South Carolina since Gaston (2004)
• 1st hurricane to make landfall north of Georgia in October since Hazel (1954)

Note: While Atlantic hurricane records go back to 1851, there are likely underestimates in storm intensity prior to the satellite era (since 1966) and especially prior to aircraft reconnaissance (since 1944).