TALLAHASSEE, Florida — Tropical Storm Debby came ashore in Florida The hurricane was upgraded to a Category 1 on Monday and quickly weakened, but it still poses a serious threat as it heads toward Georgia and South Carolina.
Tropical storms can be more deadly than some of the strongest hurricanes. In the case of Debby, the storm was expected to slow to a crawl and dump up to 30 inches (76 centimeters) of rain over several days along the coast of Georgia and South Carolina. Winds will not be the main threat, making the category of the storm much less important than the potential for catastrophic flooding.
The Saffir-Simpson scale only measures the strength of the winds of a hurricane from category 1 to category 5, the strongest. The circumference of a storm, how fast it is moving, the amount of rain it delivers, storm surge and tide are all other factors that matter.
Where a storm hits and how it moves inland are also important. Geography, population, quality of infrastructure, and the age of homes and businesses in an area can also play a role in how much damage a storm can cause. It is also important to remember that tornadoes can form regardless of the size of a storm.
Fortunately, Debby made landfall in the area where the Florida peninsula meets the Panhandle to the north, one of the least populated areas of the state. However, major cities like Savannah, Georgia and Charleston, South Carolina should take the storm very seriously.
Although Savannah’s historic downtown sits on a bluff comfortably above the Savannah River, the surrounding area, including Tybee Island, contains low-lying marshes. Charleston and the surrounding areas are particularly susceptible to flooding—especially when storms push water inland and prevent the numerous creeks and marshes from draining heavy rains into the Atlantic Ocean.
As an example of a weaker storm causing major problems, look at Hurricane Beryl, that hit Texas last month as a Category 1 storm but still caused power outages for 2.7 million customers. The storm was blamed for at least 36 deaths in Texas, including people who died in their homes from the sweltering heat after power was out for days in many areas.
Tropical Storm Fay in 2008 might be a good comparison to Debby. Fay wasn’t even that dangerous of a storm before it made four landfalls in Florida. In this case, it wasn’t Fay’s strength but its speed—or lack thereof—that proved decisive. The lethargic storm lingered over the state for days, dropping as much as 25 inches (64 centimeters) of rain in some places. Flooding killed crops and destroyed homes. Roads were so flooded that alligators swam alongside emergency workers as they rescued people stranded in their homes.
When monitoring storms, “Don’t focus on the category,” advises Craig Fugate, a former director of the Federal Emergency Management Agency who also served as Florida’s emergency management director during some of the state’s worst storms.
Fugate also advises residents to consult local weather information rather than relying too much on advisories from the National Hurricane Center and national news and weather channels.
“Everyone is focused on the Hurricane Center,” he said. “They are responsible for the intensity and the track of the storm. They are not necessarily going to have all the local impacts.”
A better place to go, says Fugate, is the Homepage of the National Weather Servicewhere you can enter a postcode and see what’s happening in your area.
“Your (regional) National Weather Service office takes all that information and localizes it, so they can tell you what kind of winds you can expect, what kind of flooding you can expect,” Fugate said. “Are you in a storm surge area? When is the high tide?”
Fugate cautions that relying on FEMA flood maps to determine a storm’s potential impact is just as unwise as relying solely on the Saffir-Simpson scale.
“People think, ‘Well, it’s a flood map. If I don’t live in the zone, I won’t flood.’ No! It’s an insurance rate map. Not living in that special risk area doesn’t mean you won’t flood, it just means the insurance is cheaper,” he said.