Those of you who may not live on the Gulf Coast, Georgia, or the Carolinas may not be familiar with the true power of a hurricane. Even on the east coast, if you live north of the outer banks of North Carolina, you may have lived through a hurricane, but still don’t know just how powerful they can get.
Hurricanes are categorized by their power on what is called the Saffir-Simpson scale. The lowest is a category one, with winds of 75 to 95 miles per hour, and the highest is a Category 5 with winds over 155 miles per hour. Each category roughly doubles the power of a hurricane, meaning that a Cat 5 hurricane is about 16 times as powerful as a Cat 1.
Threats
Hurricanes have four major ways of doing damage: wind, rain, tornados, and storm surge.
Although many people focus on the wind speed, the highest winds in a hurricane are usually within a few miles of the eyewall, and therefore don’t affect many people. Unless the eyewall, which is located with 10 miles or so of the center of the storm, passes over you, you won’t see the highest winds. Here in Florida, we have pretty stringent building codes and all homes have to be built to withstand 115 mile per hour winds. Because hurricanes weaken once the center comes ashore, and the highest winds are located near the center, the highest winds tend to be within 30 miles or so of the coast. We are pretty safe from high winds. What is dangerous about wind is that it blows debris around, and it blows for hours. Sometimes up to 12 hours nonstop.
When wind blows over the ocean for long distances, it pushes water in front of it. When that pushed water encounters land, it builds up into what is called storm surge. The tides and waves build on top of this, so a 5 foot storm surge combined with a 3 foot tide and 10 foot waves means that homes will flood miles inland with up to 18 feet of water. Luckily, we are dozens of miles inland and about 100 feet above sea level, so storm surge isn’t an issue.
Hurricanes also spawn tornados. Not much you can do about those, but they don’t affect a lot of people, comparatively.
The largest threat from a Hurricane is rain. Here in Florida, we are surrounded by swamp and we are used to torrential rain. Still, 18 to 20 inches of rain is no laughing matter. When we built our house, we picked a spot that was ten feet above the nearest wetlands. We are not in a flood prone area, and I doubt we will have problems.
Let’s compare categories to see what they do:
Category One Storm
So-called Superstorm Sandy hit New Jersey as a Category One hurricane, with 80 mile per hour winds, a 6 foot storm surge, and 12 inches of rain. People from that region still talk about this storm as if they now know what a hurricane does. Piffle. The gulf coast residents don’t even close schools for a Cat 1.
Category Two Storm
The strongest storm to hit Virginia in the past few decades was Isabel in 2021, and even then it made landfall in North Carolina as a Category 2 storm. During Isabel, Hampton roads got winds of 70 to 80 miles per hour, about 15 inches of rain, and a storm surge of about 8 feet.
The storm surge and rising waters flooded the Midtown Tunnel between Norfolk and Portsmouth with 44 million gallons of water. Workers trying to secure the floodgates on the Norfolk side barely escaped. The resulting damage closed the tunnel for nearly a month. This is more an indication that people in the area just don’t know how to prepare for a hurricane than it is the power of this storm, as the floodgates should have already been closed.
Category Three Storm
Go up just one category to a Cat3 Hurricane. This is the beginning of what they call “major hurricane.” For an example, take a look at 2023’s Hurricane Idalia, which hit Keaton Beach in the big bend area of Florida with 115 mile per hour winds, a 9 foot storm surge, and 20 inches of rain. Another great example of a Category Three was Hurricane Katrina in 2005.
Category Four Storm
Up one more category to Cat 4, and you see Hurricane Ian in 2022, which hit Fort Meyers Beach with 150 mile per hour winds, a 13 foot storm surge, and pelted the Florida peninsula with up to 26 inches of rain.
Category Five Storm
Luckily, the US doesn’t see this strong of a storm very often. Only four Cat 5 hurricanes are recorded to have ever hit the US- Michael hitting Florida in 2018, Andrew hitting Florida in 1992, Camille hitting shore in 1969 almost exactly where Katrina would in 2005, and the 1935 unnamed Labor Day Hurricane that struck the Florida Keys. Note that three of the four strongest storms recorded to have hit the US all hit Florida. I actually have lived through three of them- all but the 1935 storm.
Andrew hit Florida with 165 mile per hour winds, a 17 foot storm surge, but was a relatively “dry” hurricane with only about 7 inches of rain. Contrast that with Hurricane Michael, which dropped 13 inches of rain on the Florida panhandle. Still, it seems that Cat 5 hurricanes are so intense that they don’t drop a lot of rain.
