2014 Atlantic Hurricane Season and an El Niño

By: - May 12th, 2014

When the 2014 hurricane season officially starts on June 1, it will have been 3,142 days since the last Category 3 hurricane made landfall along the U.S coastline (Hurricane Wilma, 2005). This shatters the old record for the longest stretch between U.S. intense hurricanes since 1900. In fact, landfalls in general have been down since 2005, with a rate of 0.75 landfalls occurring per year since 2006, versus the rate of 1.78 that had been experienced since the warming of the Atlantic Multidecadal Oscillation in 1995.

Although Superstorm Sandy is still fresh in the minds of many insurers in the Northeast, insurers in hurricane-prone states could become complacent due to the lack of storms since 2005. The “doom and gloom” forecasts for the 2013 hurricane season failed to materialize, and early predictions for 2014 have already hinted at below-normal named storm activity, contributing to such complacency. These Atlantic hurricane forecasts call for hostile conditions across the deep tropics due to the development of an El Niño, which brings increased wind shear across the Main Development Region (MDR) of the Atlantic and could lead to less overall named storm formation.

There is a lot of chatter about the possible development of a “super El Niño” similar to that which occurred in 1997–1998. This type of event would drastically limit overall hurricane development. However, the Pacific Ocean is in an overall cold phase (the Pacific Decadal Oscillation (PDO)), a state which often makes it difficult to have strong, long-lived El Niño events. Instead, the PDO suggests a short-lived El Niño, but the specific manifestations of any given El Niño event greatly depend on its strength. Every El Niño event is different, but overall the phenomenon has become associated with the following:

* An uptick in the average global temperature

* Increased rainfall in Peru

* Drought in Australia

* Warmer than average temperatures in Alaska

* Elevated rainfall in California during moderate and strong events

* Dry weather in the Pacific Northwest states

* Increased snowfall in the Mid-Atlantic, especially for moderate El Niño events

* Cooler and wetter than average conditions in the Southeast U.S.

* Increased hurricane activity in the eastern tropical Pacific basin

* Depressed hurricane activity in the tropical Atlantic

While El Niño years generally have lower instances of named storms that make landfall, there are plenty of examples of El Niño-influenced hurricane seasons that have impacted the U.S. coast. Below is a look at such years, as well as the number of storms that made landfall and the adjusted insured loss in 2014 dollars.

Year # of Landfalling Storms Adjusted 2014 Insurance Loss
1957 2 $1,489,000,000
1965 2 $11,177,500,000
1969 1 (Camille) $8,250,000,000
1976 5 $300,000,000
1991 1 (Bob) $1,730,000,000
1992 1 (Andrew) $28,005,000,000
2002 6 $902,050,000
2004 6 $28,387,500,000

As we learned last year, seasonal forecasting has its challenges. Currently, there is a 75% chance of an El Niño developing this summer during the peak of the Atlantic hurricane season. However, in 2012 when an El Niño watch was issued, an El Niño never formed. In fact, since 1997 there have been five threats of a super El Niño that never developed. Therefore, taking into account the uncertainty in any seasonal climate forecast and the history as shown in the chart above, there can be an increased threat from tropical storms even in El Niño years. The 2014 seasonal forecast might also focus on other regional climate forces. One of these forces might be that the Sea Surface Temperatures (SST) off of the Eastern Seaboard of the U.S. are warmer than normal, which not only adds fuel to storms like Superstorm Sandy, but also could lead to deepening of pressures if any tropical disturbances tap into this potential fuel source later this summer. This warmer water also likely means that storms could develop closer to the U.S. coastline.

The new seasonal hurricane forecasts, which will roll out around June 1, tend to have increased accuracy as compared to the spring projections. These forecasts will continue to reflect the evolution of the El Niño, which can be followed on the Climate Prediction Center’s website (El Niño/La Niña Current Conditions and Expert Discussions). BMS will also provide updates throughout the season, but expect new seasonal forecasts to call for named storm formation to be below normal for the 2014 Atlantic hurricane season.