In the Know: Why wasn't there much storm surge from Wilma?

Reprinted from the April 12, 2006 Daily News

Q. Why was there such a large storm surge with Hurricane Katrina, but not such a large storm surge with Hurricane Wilma in Naples? R. O'Brien, Naples

A. Katrina devastated Louisiana and Mississippi when it came ashore last August, and caused hundreds of deaths. Wilma, on the other hand, caused considerable damage to South Florida when it came ashore near Marco Island in late October but resulted in relatively few deaths.

Both Wilma and Katrina were at one time Category 5 storms, and both were Category 3 storms at landfall — though Katrina was a bit stronger.

Jim Farrell, chief meteorologist at WINK-TV, said the main difference was that Katrina was moving more slowly than Wilma.

Katrina's slower forward speed contributed to its higher storm surge — a dome of water caused mainly by the power of the wind blowing across the waters, Farrell said.

The differences in the coastal topography between Florida and the northern Gulf coast also played some role.

Katrina's storm surge was estimated at between 15 and 35 feet, Farrell said.

As is the case with most hurricanes, Wilma's surge was greatest in the right-front quadrant, said Jim von Rinteln, an emergency management coordinator for Collier County.

This means that points to the east of Marco Island got the worst of the surge.

Indeed, Everglades City did get a storm surge of about 6 feet, and the surge was even higher at Chokoloskee and points south, von Rinteln said.

The surge at Naples — west of Wilma's landfall — was only about 2 feet, von Rinteln said. (In contrast, Tropical Storm Gabrielle brought about 4 feet of storm surge as it passed by Collier County on Sept. 14, 2001.)

Hurricane Donna in 1960 brought a storm surge of about 11 feet to Naples, which produced "serious damage," von Rinteln said.

So what would it have been like if Wilma had brought 6-foot storm surge to Naples? Von Rinteln said there would have been much more damage to the beaches and flooding of homes along the coast.

Before Wilma struck, dire predictions of 12- to 14-foot storm surge prompted Collier officials to evacuate areas south and west of U.S. 41.

If Naples actually had gotten such a large storm surge, von Rinteln said, "we'd still be cleaning up."

It's difficult to pin down exactly what the storm surge will be, because a hurricane's variables are in flux, and the forecast has to be made early enough to give emergency coordinators time to issue evacuation notices.