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Tropical Storm Debby Spawns Dangerous Tornadoes

Tropical Storm Debby near Florida
A ghostly Tropical Storm Debby is drenching Florida and surrounding regions. (Image credit: NOAA.)

As if flooding rains and dangerous storm surge weren't enough, Tropical Storm Debby is producing yet a third hazard for beleaguered Florida residents this week — tornadoes.

The fourth storm of the 2012 Atlantic hurricane season, which has gotten off to an unusually early start, spawned as many as 20 tornadoes yesterday (June 24), one of which killed a woman in her home in south-central Florida.

The swarm of tornadoes severed power lines, ripped roofs from buildings and knocked tractor-trailers into ditches. 

Typical behavior

It's "not at all unusual" for tropical storms and hurricanes to generate tornadoes, said Dennis Feltgen, a meteorologist and spokesman for the National Hurricane Center in Miami. [The Tornado Damage Scale In Images]

"You typically see them spinning off tornadoes if bands of rain are over land," Feltgen told OurAmazingPlanet — and Debby has been pummeling Florida and now parts of southern Georgia with punishing rains.

Tornadoes that spring from rainstorms brought by hurricanes and tropical storms are typically smaller than the tornadoes produced by the supercell thunderstorms that frequent Tornado Alley, yet the smaller twisters can be every bit as dangerous.

"These are quick-forming tornadoes," Feltgen said. In addition, these so-called rain-wrapped tornadoes are often difficult to spot — rain shrouds the funnel clouds, adding to forecasters' woes.

"It's very difficult to get a warning out for them," Feltgen said. "The lead time is much smaller."

And although tornadoes have done serious damage, it is the nonstop barrage of water that is posing some of the greatest hazards in areas feeling Debby's effects.

Water, water everywhere

Largo, a city on Florida's west-central coast, received more than a foot of rain — 12.5 inches (32 centimeters) — in 24 hours. "These tropical bands can produce a lot of water in a very short time," Feltgen said.

Forecasters say the storm could drop as much as 25 inches (64 cm) of rain in some areas. "In some places we could be measuring rain in feet, not inches," Feltgen said.

Tropical Storm Debby has remained stubbornly in one place over the last day or so, and is forecast to move very little in the next 24 hours — which is adding to the high rainfall totals.

According to a recent update from the National Hurricane Center, the storm is creeping toward the northeast at a mere 3 mph (6 kph), yet is packing winds of up to 45 mph (75 kph), and continuing to generate flooding rains east of its center.

"Folks in the warning area need to take this storm seriously," Feltgen said. "The threat of horrific rainfall, tornadoes and storm surge are three factors we are very concerned about, so do not take this thing lightly."

Reach Andrea Mustain at Follow her on Twitter @AndreaMustain.Follow OurAmazingPlanet for the latest in Earth science and exploration news on Twitter @OAPlanet. We're also on Facebook & Google+

Andrea Mustain was a staff writer for Live Science from 2010 to 2012. She holds a B.S. degree from Northwestern University and an M.S. degree in broadcast journalism from Columbia University.