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Wednesday, December 4, 2019
The Evolution of Hurricane Power and Destruction

The evolution of Hurricane Power and Destruction


A tropical wave came off the coast of Africa on August 27, 2017 and eventually became category 5 Hurricane Irma, the most intense storm to strike the U.S. since Katrina in 2005.  Hurricane Irma lasted 14 days, causing $77B in damage in the Caribbean and USA. 


The wind field of this storm was approximately three-times that of Hurricane Andrew, which was the last Category 5 hurricane to hit the Bahamas, Florida, and Louisiana, back in 1992.  Unlike Hurricane Andrew, the cone of uncertainty for Hurricane Irma encompassed the entire peninsula of Florida.  Close to six and a half million people tried to evacuate; instead, many spent hours on Interstates 95, 75, and the Florida Turnpike, trying to go north or west, only to give up and try to find gas so they could retrace their route and get back home before the storm hit.


Florida opened 700 shelters, housing approximately 190,000 people, 40% of whom were in South Florida. 60 additional shelters, housing “special needs” evacuees were also opened[1].  In all, 1.2% of the entire population of South Florida had to be housed for Hurricane Irma.


Lesson learned: If you didn’t make arrangements and get out of South Florida well in advance of the storm, you didn’t get out.  You “evacuated in place.”


Hurricane Harvey made landfall in August 2017 in Texas and Louisiana, causing catastrophic flooding and 102 deaths. In only four days, many areas received more than 40” of rainfall, with a peak accumulation of 68.58.” Harvey was the wettest tropical cyclone on record, damaging or destroying an estimated 300,000 structures and 500,000 vehicles in Texas alone. The National Oceanic and Atmospheric Administration estimated total damage at $125 billion, with a 90% confidence interval of $90–160 billion, making Hurricane Harvey the costliest storm on record.


Lesson learned: Warmer air holds more water that has to go somewhere.  68” is a deluge that will overstress any existing stormwater system.


Hurricane Michael was the first category 5 storm to strike the Florida Panhandle.  While the windspeed, rainfall, and damage number weren’t staggering, the storm spun up quickly and its 14-foot storm surge and Category 5 winds flattened or swept away houses, cars, trees, and crops in Mexico Beach and Panama City, FL.  1.2 million people were without power.  Remnants of homes were scattered across U.S. Route 98, which had large sections of pavement washed away. Entire neighborhoods in Mexico Beach were reduced to nothing but bare foundation slabs, and numerous vehicles, businesses, apartment buildings, and hotels throughout the community were destroyed or severely damaged. Countless trees in the area were snapped and denuded.  The storm wreaked destruction at Tyndale Air Force Base as well.


Lesson Learned: Infrastructure, buildings and codes must be robust enough and updated to withstand hurricane force storms, so that “recovery” is even possible.


Hurricane Dorian didn’t even hit the U.S. mainland but leveled the Northern Bahamas. It “sat and spun” for 24 hours and reduced parts of Abaco and Grand Bahama to toothpicks. Had that storm stalled 50 miles west of where it did, the infrastructure, housing, and water supply of South Florida would have been equally devastated. 


Within the span of only two years, these four storms have demonstrated that we must recalibrate everything, including ourselves, to be better prepared to deal with the storms and put ourselves in a position to be successful in recovery.  The model has always been a four-step process: prepare, evacuate (or safely evacuate in place), assess damage, and recover.  This recent history suggests we need a fifth step – reconstruction.  Storms once categorized as “100-year events” are now occurring with greater frequency, if not yearly. Paths of destruction are bigger, damage more expensive, and aftereffects (such as loss of revenue from tourism, or people moving out and not returning) last much longer.


While our building codes set the standard; Hurricane Dorian blew right past them.  They were set and updated for windspeeds 20-25mph less than those recorded during that storm.  What does it take to withstand 185 mph winds for 24 hours?


Our storm surge and storm water handling capability in the U.S. is not even close to dealing with the volume of Hurricane Harvey’s deluge.


The uncertainty of the strike point and the sheer size of Hurricanes Irma and Michael made it nearly impossible to evacuate the number of people that live on the peninsula we call Florida. And shelter capacity is too low to house everyone “in place.” 


Hurricane learning is episodic: we learn from the last one and it informs what we do (or not do) for the next one. If these four storms have taught us anything, it’s that we are not ready for the next big one.  Now that the 2019 “season” has ended, we’ll go back to doing what we always do – breathe a sigh of relief, enjoy the ‘winter’ weather, and next May 15th, as we prepare for the new storm season, we’ll start to worry all over again.

What should we do, this time, to start preparing for the “new normal” in hurricane destruction?  


[1] Evacuation to a special needs shelter requires advanced planning and notification to the shelter.

Posted by: Marine Advisory Committee @ 10:00:00 am 
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