In an average year, eight tornadoes strike South Florida. But this is no average year.
In less than three weeks, five twisters raked sections of Broward, Palm Beach and Miami-Dade counties – the last three a week ago Tuesday — and conditions are ripe for more.
“Expect more, absolutely,” said Greg Carbin, a meteorologist at the Storm Prediction Center, an agency of the National Oceanic and Atmospheric Administration in Norman, Oklahoma. “The prospects for this to occur again are relatively good.”
Why the region is bracing for more damaging storms during what is normally the dry season is not entirely the fault of El Nino, an abnormal warming of the equatorial eastern Pacific that is unusually strong this year.
But, “El Nino helps set the stage by creating a stronger and more southerly jet stream,” the west-to-east river of air that helps propel and fuel stormy weather, said Robert Molleda, a forecaster at the National Weather Service in Miami.
In order to form, tornadoes need thunderstorms, and a state flanked by the warm waters of the Gulf of Mexico is fertile breeding ground. But tornado formation also depends on the right mixture of other ingredients – atmospheric instability, wind shear, frontal systems – and those are abundant this year as well, forecasters say.
As thunderstorms intensify, wind speeds change and can lead to rotation within the system, Carbin said. From that rotation tornadoes are born.
“Now for any one tornado, it is hard to say it’s connected to El Nino. But El Nino enhances the subtropical jet stream,” Carbin said, pushing it south and ushering in more moisture and cold fronts that can collide to produce violent weather.
“So as we’ve been saying for the past couple of months, the likelihood for tornadoes is greater in February and March in Florida and all along the Gulf Coast,” Carbin said.
The good news is that Florida-born tornadoes are usually relatively small and short-lived, especially when compared to the monster twisters that form in the plains states in the spring. Florida has never seen a category EF5 tornado, with winds of 200 miles an hour, such as the one that killed 24 people and destroyed much of Moore, Oklahoma, in May 2013, according to the National Weather Service.
The storms which caused damage but no deaths in Florida most recently were rated EF1, the least powerful category, with top winds of 65 to 85 mph.
During the January outbreak, the tornado blamed for two deaths in Manatee County was rated EF2, with winds of up to 127 miles an hour.
The most deadly tornado outbreak in Florida history occurred in February 1998, when seven twisters swept through the east-central part of the state, killing 42 people and injuring more than 260 others, according to the National Weather Service.
That toll, and this year’s storms, will be on the minds of emergency managers when Florida conducts its annual tornado drill, part of the 2016 Florida Severe Weather Awareness Week, beginning Monday. The drill starts with a radio tone and advisory to be broadcast at 10:10 a.m. on Feb. 26.
“This is an occasion to get people, schools and businesses, to think about what they will do in the case of an emergency,” said Amy Godsey, chief meteorologist for the state’s Division of Emergency Management, “Think about the best place to take shelter, know where you would go.”
Godsey said this year’s drill carries “a little extra meaning because we’ve had more severe events than usual already, and there may be more to come.”
Forecasting and lead times for storm warnings are better now than they were in 1998, Godsey said.
“With advanced warnings, there shouldn’t be tornado deaths,” she said. “But there is still work to do getting people to understand how to receive warnings. It could save your life.”