‘Catastrophic flash flooding possible’ with heavy rain falling on still-flooded South Florida

Heavy rainfall has been inundating South Florida for a third day in a row on Thursday, with flash flood warnings in effect from Miami to Fort Lauderdale, after Wednesday’s storms transformed roads into canals and caused water to seep into homes.

Flash flooding is likely to occur at a faster rate than usual as the areas around Miami are already saturated from more than a foot of rain in the past two days.

Nearly 1.7 million people living in South Florida – including the cities of Hialeah, Aventura and Doral – are under a flash flood warning Thursday evening as a line of storms approach the Miami area and bring the potential to produce several inches of rain in a short period of time, according to the Miami-South Florida office of the National Weather Service.

“Significant flash flooding (is) expected over urban areas, (with) locally catastrophic flash flooding possible,” the Weather Prediction Center warned earlier Thursday.

High risk days are exceedingly rare — happening on fewer than 4% of days each year on average — but account for more than 80% of all flood damage and more than a third of all flood deaths in the US.

More than 8 million people are under flood alerts Thursday, including Fort Lauderdale, Miami and Naples. Another 4 to 8 inches of widespread rain is expected through Friday, but it’s possible some spots record nearly a foot of rain.

Six to more than 20 inches of rain has deluged South Florida since Tuesday morning, prompting Florida Gov. Ron DeSantis to declare a state of emergency for Broward, Collier, Lee, Miami-Dade and Sarasota counties. While the state is no stranger to drenching rain, heavy rain events are getting even heavier as the world warms due to fossil fuel pollution.

Ongoing flooding resulting from past rainfall is one of the main reasons the flood risk is so high Thursday.

Floodwaters haven’t had time to fully recede and some communities in and north of the Miami metro remained underwater Thursday morning, aerial imagery showed.

That was the case in Hallandale Beach – located just north of Miami – where nearly 20 inches of rain had fallen, and some mobile home parks were still underwater, said Broward County Sheriff’s Office Fire Rescue Battalion Chief Michael Kane.

Severe flooding there on Wednesday covered cars up to their windshields, forcing some drivers to abandon their stalled-out vehicles and wade to safety. Others had to be rescued.

“We had to use our boats to rescue people standing on top of the roofs of cars,” Kane told CNN. Kane’s office received 175 calls for help in Hallandale Beach alone.

People walk through a flooded street in Hollywood, Florida, on June 12, 2024. - Joe Raedle/Getty Images
People walk through a flooded street in Hollywood, Florida, on June 12, 2024. - Joe Raedle/Getty Images

Resident Kait Madrigal spent five hours stuck in her car Wednesday after it became suddenly surrounded by floodwaters on her way to work near Hollywood, Florida, she told CNN. She was able to park on the sidewalk to get to higher ground but began to panic as the water rose and cars began to stall out around her.

“If I was to open my car door, I would’ve just had a ton of water rushing in. I would’ve been out of luck big time,” the 25-year-old said.

After hours of unrelenting rain, Madrigal waded through the water and was able to find a possible exit route. Fearing she may become trapped all night, she drove out and was able to get home safely, she said.

Several local officials have warned against trying to drive through murky floodwaters and are urging storm-weary South Floridians to stay home. Most flood-related drownings occur when cars unknowingly drive into deep water, the Florida Department of Highway Safety said.

Fort Lauderdale, where the mayor declared a local state of emergency, received its entire average June rainfall of around 9.5 inches in just 24 hours Wednesday.

Miami International Airport and Fort Lauderdale-Hollywood International Airport led the nation with the most flights canceled or delayed Wednesday, with more than 1,200 disruptions. The air travel woes are expected to continue through the end of the workweek.

A vehicle sits in floodwaters in Hollywood, Florida on June 12, 2024. - Joe Raedle/Getty Images
A vehicle sits in floodwaters in Hollywood, Florida on June 12, 2024. - Joe Raedle/Getty Images
Floodwaters surround a home on June 12, 2024, in Hollywood, Florida. - Joe Raedle/Getty Images
Floodwaters surround a home on June 12, 2024, in Hollywood, Florida. - Joe Raedle/Getty Images

In Broward County, the severe storms prompted school officials to postpone the demolition of the Marjory Stoneman Douglas High School building where a gunman killed 17 people in 2018.

Many South Florida residents had only just finished repairing their homes after catastrophic flooding in April 2023, only to find water lapping at their doorsteps Wednesday.

Anna Rysedorph, a resident of the Broward County neighborhood of Edgewood, prepared for the worst as water circled her ankles in her home.

“I put the dogs in, I’m all packed up. I pretty much got everything in bins and we’re ready to go,” Edgewood resident Anna Rysedorph told CNN affiliate WSVN Wednesday. “My husband’s like ‘Don’t panic, don’t panic,’ but you know, I’m not gonna be caught unprepared.”

Significant flood risk Thursday

Multiple rounds of torrential downpours fueled by a firehose of tropical moisture from parts of the Caribbean are drenching the southern Florida Peninsula on Thursday.

Friday will also be another drenching day for South Florida, even as the robust tropical moisture fueling the soaking storms slowly starts to shift out of the area. All told, multiple locations could end up with more than two feet of rain Tuesday through Friday.

Wet weather is likely to continue over the weekend, just not to the severity of the past several days. But even the light-to-moderate rainfall rates of typical June showers and thunderstorms could cause additional flooding issues and prevent ongoing flooding from receding.

If there’s any silver lining, it’s the rain is beneficial to areas suffering through drought. Half of Florida is experiencing abnormal dryness or drought conditions, with the worst drought centered in the bull’s-eye for the heaviest rain, according to the US Drought Monitor.

CNN’s Sara Smart and Jamiel Lynch contributed to this report.

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