Historically, Labor Day weekend is no stranger to hurricane impacts to the U.S. Coastline, and this year is no exception. After all, the peak of the season is just ten days away. With winds of 65 mph, Tropical Storm Hermine is less than 10 mph from being classified as a hurricane. And located 170 miles southwest of Apalachicola, Florida and 220 miles west southwest of Tampa, Hermine threatens insured losses. Several models are now coming around to the idea that the long-standing Florida hurricane drought of 3,966 days will soon end. As a reminder, the last Florida landfalling hurricane was Wilma that struck on Oct 24, 2005, near Cape Romano. (You may also recall category 2 Hurricane Arthur, but despite its landfall in 2014, it failed to cause significant insured losses.)

So will Hermine cause large insured losses? Unfortunately, we cannot depend on historical data to help predict since there is little hurricane history in Hermine’s expected path. The three best analog events for the forecasted landfall location are Hurricane Alma (1966), Tropical Storm Allison (1995), and Storm #5 (1941). Storm #5 and Alma were category 2 hurricanes at landfall, so finding a good benchmark historical hurricane to estimated insured loss is difficult in this case, but given these historical events and the hazards outlined below, a multi-million dollar insurance industry loss cannot be ruled out.

The factors that will lead to insured loss at this point will be multifaceted.

Flooding Rains and Storm Surge

Many areas along the Florida Gulf Coast have already seen significant rainfall. Here is what has fallen so far.

RainfallSofar_Hermine
Many areas of northern Florida will see between 3” – 12” more of rainfall through Saturday. And although the forecasted area of landfall is mostly made up of large tidal marshlands resulting in a coastline that is not as densely populated, it is very prone to storm surge.

Storm surge could top several feet in some areas, despite the fact that Hermine will be a minimal hurricane at landfall.  In fact, data suggest Hermine has the kenetic energy of a category 1 hurricane already.

Wind

Using Verisk Climate forecasted wind swath, BMS clients can now better understand wind impacts to specific risks. This high-resolution model wind field shows hurricane force winds rapidly weaken inland due to frictional effect.

iVision_Hermine_VC_WindsSept1

But this does not mean the winds won’t be strong enough knock down some trees, especially given the moist soil conditions in the area. In fact, this section of Florida is not just beach. There are quite a few trees in the north, especially around the Apalachee Bay. When you combine the foliage with the lack of a hurricane activity over the last 10 years, a natural culling of weak and damaged trees and branches can be expected. And, of course, even tropical-storm force winds can cause minor damage to structures.   One also can’t rule out a tornado or twoSoutheast_biomass

 

 

After Florida Landfall
Even though modeling over the last 14 days has not been the best for Hermine, it is starting to come around. Much depends on the track Hermine takes once inland over Florida. If Hermiane tracks back out over the warm waters of the gulf stream, expect Hermine to re-strengthen into a powerful coastal storm. There is some model disagreement about whether Hermine will become a hurricane again, or a post-tropical storm, but regardless, high surf and strong winds will result. Some models even stall Hermine for a few days off the New Jersey coastline near Labor day. The strength really depends upon whether Hermine stays overland along the east coast of the U.S. or just off shore.

Lastly we are still watching Invest 92L  in the Atlantic.  It is fighting dry air and weak so there is no threat at this point in time of development.

Interesting Point
The first Tweet was sent on March 21, 2006, months after Wilma in 2005. Hermine is likely Florida’s first hurricane in the Twitter era.