BMS Tropical Update 8/27/2017 12 PM

By: - August 27th, 2017

Bad Situation Getting Worse

Another day that I am overwhelmed with data and the impacts from Harvey and unfortunately today the data is suggesting the rainfall amounts are likely higher than what was predicted to fall over the seven-day period starting this past Thursday.  I will once again try to focus on insurance industry impacts from Harvey which has now turned to major flooding in the Houston area and will likely be one of the costliest flood events in U.S History.

Harvey Position and Forecast

Harvey, now a tropical storm with winds of 40 mph, is currently centered near Yorktown, TX or about 70 miles east southeast of San Antonio, TX and moving at 1 mph to the southeast.  Harvey is still not forecasted to move out of Texas until later next week, therefore days of rain are still expected on top of what has already fallen.  The general consensus is that Harvey will weaken to a tropical depression and move slowly back towards the coastline and work its way up the Texas coastline toward the Texas Louisiana border.  Some models suggest Harvey could move back over the Gulf of Mexico where it could regain some strength as it moves toward the border, but the wind damage threat is mostly over for Harvey and any wind damage would come from tornadoes or isolated thunderstorm.

Because Harvey will continue to draw in warm Gulf of Mexico moisture, its rain shield will continue move to the northeast along its track.  The heaviest rain will move into Louisiana as Harvey moves to the Northeast over the next several days.

Radar Image showing that moisture trail feeding heavy rainfall into the Houston area.

Tornadoes

I only briefly touched on the tornado threat leading up to Harvey’s landfall.  So far Harvey has spawned 20 confirmed tornadoes and some of these tornadoes have cause insured loss and more tornadoes can be expected as Harvey continues to impact the area over the next few days.

Areas of Tornado Yesterday are represented by Tornado Warnings issued by the NWS

Flood & Rain

Since Monday the forecast have called for over 20” of rain to fall from Harvey as it stalls out along the Texas coastline.  These forecasts continue to show that another 26” of rain could still fall over the area over the next 7 days.   This means that Harvey will likely go down as one of the heaviest rainfall events form a Named Storm in history as total rainfall reaches over 50”. This is very impressive considering Texas is no stranger to very heavy rainfall events. Just last year the Tax Day flooding event in Houston area caused widespread flooding, dumping as much as 23.5″ in 14.5 hours in Pattison, TX and causing insured losses of $584 million dollars according to PCS.

Tropical Storm Amelia in 1978 still holds the record for most rainfall over the state from a named storm as it dumped 48” over a five-day period and Harvey could just surpass this event before the end of the week.

Tropical storm Claudette 1979 still remains the twenty-four-hour rainfall record for any location in the United States with 42” of rain falling.     

More recently Allison 2001 caused massive flooding in the Houston area.

The rain continues to fall from Harvey, below is the most recent rainfall totals as viewed in BMS iVision in its severe weather module which has rainfall maps over the last seven days.

 

 

Radar estimated storm total for Harvey so far and the areas of major river flooding.  Basically any body of water is likely to see record flooding.Below is a Free Flood mapping tool created by FM Global that can help determine areas of flood hazard. This is not a flood map for Harvey, but it’s a safe bet any areas shown as flood areas are or will be flooded from Harvey

Insured Loss

It is now easy to understand that Harvey will easily reach well over $10 billion USD in economic loss.  The winds and surge losses are still being assessed and given the footprint of affected areas, it is going to take weeks until full assessments are gathered to understand the totality of the damage.   However, from what we know now the general consensus seem the wind related losses will likely be in excess of $2 Billion in insured loss with a much higher economic loss. If you combine this with what historical flood events have done just to the Houston area in the past (Allison 2001 $3.4B adjusted – $10B economic) insured losses are likely in excess of $5 billion dollars.   In fact, for more perspective the catastrophic flooding that occurred in Louisiana last year (August 11 – 15) caused $1 Billion in insured loss according to PCS.   That flooding occurred over an area with about 850K people.  Houston has 7 times more population being the fourth largest city in the U.S. and the rainfall totals will be higher than what occurred in Louisiana last year.

In all the figures above I have not even accounted for NIFP losses which will just add to the expected losses.  As indicated earlier in the week flood coverage is highest along the Texas coastline, however, according to NIFP many areas along the coastline still fall below 20%  coverage.


Clearly this could likely be one of the largest NFIP flood payout in recorded history which will require a major relief bill.  It will likely have major impacts to the flood reform that will be discussed in Washington over the next several months.

Storm off the East Coast

I expect the storm off the Southeast Coast Invest 92L  to develop into a named storm (Irma) but this will not be a threat to the U.S. Coastline.

There is a medium chance of more storm development off the coast of Africa later this week.

 

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