Wind, Water & Exposure – Hurricane Helene’s Risks – Top 3 Takeaways – September 26th, 2024
- Wind. It’s human nature to pay the most attention to the category of the hurricane and the center of the projected path...just like it’s human nature to look at an accident on the side of the road. Both of those situations can lead to problems. Yes, you should account for wind risks with any hurricane, including Helene, that may impact us. But that’s not the only wind consideration. As we’ve seen on Florida’s east coast with previous hurricanes that have made landfall on Florida’s Gulf coast, one of the most significant risks that come with hurricanes are tornadoes. Not only are tornadoes possible in hurricanes, but they’re also likely, and for those outside of the point of impact, are often the greatest wind risk faced. Two years ago, Hurricane Ian spawned the most tornadoes we’d seen for a Florida hurricane since Irma in 2017 – another hurricane that made landfall on Florida’s west coast but that brought the east coast numerous tornadoes in the process. According to the National Weather Service, 20% of all tornadoes during the months of August and September occur in hurricanes and they’re most likely to occur 50 to 250 miles from the eye of the storm – which places most of the state on watch today as Hurricane Helene tracks north through the Gulf on its way towards Apalachicola. The average major hurricane spawns more than two dozen tornadoes. In certain instances, like Hurricane Ivan, more than 100 are possible (117). Tornadoes happen quickly generally, but in hurricanes there’s typically fewer than five minutes notice before one touches down. According to the National Hurricane Center Helene’s hurricane force winds extend 60 miles from the center of the storm. Helene’s entire wind field is large, with tropical storm force winds extending up to 345 miles from the center of the storm which is why nearly the entire state of Florida is under at least a tropical storm warning today. Current forecasting suggests a lower than 20% chance of sustained tropical storm force winds today for Southeast Florida through the Treasure Coast (defined by the National Hurricane Center as winds of 39 mph or greater for a minimum of 1 minute), though tropical storm force gusts are likely. The peak winds in our area will likely occur between 2 to 4 this afternoon. Sustained winds tend to get the most attention, however they’re only part of the equation. In recorded US history 8% of deaths attributed to hurricanes are due to impacts from sustained winds, 3% of deaths are from tornadoes. That’s a preview of how deadly water tends to be.
- Water. Water is to hurricanes what a center is to a quarterback. Without the center the quarterback isn’t getting the ball. The quarterback gets all the attention, and the center is only noticed if there’s a missed block or fumbled snap. Seldom do we pay attention to the water risk to the extent we do wind risk, but it's almost always the biggest issue. From storm surge to flooding – nothing’s been more deadly in hurricanes than water. 27% of all deaths have occurred from flooding and 49% from storm surge according to the National Hurricane Center. On Florida’s east coast we don’t have a meaningful risk of storm surge, but flood advisories are out, as areas prone to flooding are likely to see some of it happen throughout the day today. Florida’s Gulf coast is obviously a vastly different story. The peak storm surge forecast calls for a peak surge of 3-5 feet along the Southwest Florida coastline up to 10 to 15 feet in the Big Bend near the expected landfall. The good news is that it’s a lightly populated area. The bad news is that it’s likely to be devastating for the people who live in coastal areas in the Big Bend. For most of us on Florida’s east coast, the biggest issue we tend to run into with water during storms, aside from flood prone areas flooding, is saturated soil with gusts of wind leading to downed trees, limbs and power lines (although that’s continued to improve with the increase in underground powerlines). In fact, in most scenarios that has been the deadliest risk for Floridians resulting from hurricanes...not what happens during the impact of the storm but what happens after impact.
- Exposure. Perhaps the most underappreciated impact of a hurricane is what happens after it’s over. And for Floridians it’s proven to be the most dangerous - time and again. Take 2017’s Hurricane Irma for example. 92 people died in the US due to the storm, but only ten during the storm. The rest of those deaths are referred to as “indirect”. The majority of indirect deaths are due to the varying effects of exposure and often a bit of carelessness. Warm weather and no power for extended periods of time have proven to be a problem historically. For the purpose of Hurricane Helene, this isn’t a concern for those on Florida’s east coast, only near the point of impact at landfall tonight. But it does tend to be among the biggest issues for those who opt to stay as opposed to evacuating hard hit areas. It's something to be mindful of if you have friends and family on the other coast and potentially in harm’s way.