The gentle slope of the eastern coastline puts most of the communities in Frances' path less than 10 feet above sea level. As CBS News Correspondent Lee Cowan reports, that can be a problem when the expected storm surge could be well above that.
If the current forecast holds, Frances' winds will push a bulge of seawater as high as 11 feet onto the shore.
"It will surprise me if I still have a house when the storm leaves," says resident Ken Wiggins. "But there's nothing you can do about it, just hope for the best."
Just one cubic yard of the Atlantic Ocean weighs 1,700 pounds and can act like a bulldozer with a blade several miles wide, shoving everything out of its path.
It happened in Galveston in 1900, when more than 6,000 people drowned.
In 1928, another 2,000 were killed when the waters of Florida's Lake Okeechobee were shoved over its levees.
But the storm surge is only part of the water worry. Frances is now crawling at less than 10 miles-per-hour, giving it more time to drop more rain - up to 20 inches is predicted over the next three days.
And that's the kind of scenario emergency crews fear the most. Swift water rescues are some of the most dangerous of all and the least practiced.
"A lot of fire departments choose to ignore it, simply because they don't run that many calls," says George Lewis of Fairfax County Search and Rescue.
And the slower Frances moves the longer it will take rescuers to get where they need to go.
"It makes it impossible for those who are in emergency management police and fire … to come and get access," says Eric Williford of Weather Predict Inc.
People who live along the coast have learned to get out of the way. It's residents further inland who remain more complacent, forecasters say. For this reason, the number one killer from hurricanes isn't the wind, it's the water.