CNN
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Substantial downpours have inundated Fort Lauderdale and parts of South Florida Wednesday night in a once-in-a-half-century rainfall event, leading to a flash flood emergency in Broward County and one mayor calling the deluge the “most severe flooding that I’ve ever seen.”

Between 14 and 20 inches of rain have drenched the greater Fort Lauderdale metro area since Wednesday afternoon, according to an early Thursday morning update from the National Weather Service office in Miami.

“Even though the heavy rain has concluded, numerous roads remain closed,” the weather service said, adding that flooding is expected to persist.

Broward County is under a flood warning through 8 a.m. ET, the weather service in Miami said.

Earlier, Fort Lauderdale was “experiencing severe flooding in multiple areas of the city,” Fort Lauderdale Fire Rescue said on social media, warning to stay off the roads as vehicles may become stuck or submerged.

A flash flood emergency – the highest level of flood warning – that was in effect for portions of South Florida, including Fort Lauderdale, expired early Thursday.

“This is a PARTICULARLY DANGEROUS SITUATION,” the NWS warned. “Move to higher ground now! This is an extremely dangerous and life-threatening situation. Do not attempt to travel unless you are fleeing an area subject to flooding or under an evacuation order.”

Hollywood, Florida, Mayor Josh Levy told CNN that “city crews are doing everything they can” to deploy pumps wherever possible and keep drains clear.

“We’ve recorded over 12 inches of rain since midnight, and that’s on top of consecutive days of seemingly nonstop rain,” Levy said. “The ground was already saturated so there is extensive flooding all over our city and throughout South Florida. Many roadways are impassable. Lots of vehicles got stuck and left abandoned in the middle of our roadways.

“I’ve lived here my whole life. This is the most severe flooding that I’ve ever seen,” he said.

Fort Lauderdale officials have activated its emergency operations center and will be issuing a proclamation of a local state of emergency, saying in a statement early Thursday morning that airboats and high-clearance buggies have been secured from the county sheriff’s office and the Florida Wildlife Commission.

“Staff is assessing park facilities to convert them to staging/reunification centers for individuals impacted by the flash floods. We expect to open these as soon as possible,” the city said. There is “no power at City Hall. We have reports of water flooding the first floor of the Transportation and Mobility (TAM) building.”

The city’s system is designed to take on at least 3 inches of rain in a 24-hour period but they’ve “had neighborhoods receive more than 12” of rain. Service crews will be out to respond to flooding reports and concerns.”

CNN has reached out to city and county officials for additional information.

Four tornado warnings were reported in the area Wednesday.

There is also a slight risk, Level 2 of 5, for severe storms Thursday in parts of Florida, including Fort Lauderdale, Miami and Jacksonville, according to the Storm Prediction Center.

Officials have asked residents to avoid driving or traveling in Fort Lauderdale amid the storms.

“Police and Fire Rescue continue to answer calls for service,” the city of Fort Lauderdale said in a news release on Wednesday evening. “Public Works staff are clearing drains and operating pumps to mitigate the water as quickly as possible. Efforts have been made to relieve traffic congestion through prioritized signaling to assist individuals leaving the City. We are requesting drivers to stay off the roads and avoid the City of Fort Lauderdale until the water has subsided.”

The flooding impacted rush hour traffic Wednesday and led to the closure of a tunnel, the city said.

“The Henry E. Kinney Tunnel is closed. Please avoid the area. The weather conditions combined with rush hour traffic are compounding issues in the downtown area,” the city said.

The Broward Sheriff’s Office said in a statement Wednesday it is “being inundated with non-emergency 911 calls regarding the inclement weather” and asks residents to use 911 only for “true emergencies,” also telling residents to avoid driving and to call a tow truck company if a vehicle is stranded and not in an emergency.

Some local services are shuttering Thursday. The Fort Lauderdale-Hollywood International Airport is closed due to ongoing flooding in the vicinity and will reopen at noon, according to an update from the airport. The airport’s departure level reopened to allow people to exit the area, the airport said early Thursday morning.

The Brightline train service has been temporarily suspended between Miami and Fort Lauderdale, the service said on social media.

Additionally, Broward County Public Schools announced the district will close Thursday.

Observed rainfall totals in and around the Fort Lauderdale area indicate at least a 1-in-50 year rainfall event Wednesday, according to a CNN analysis of precipitation statistics from the National Oceanic and Atmospheric Administration, with rainfall totals as of 9 p.m. ET Wednesday exceeding 12 inches in 24 hours.

Some places may have seen even more extreme rainfall. According to the latest flash flood emergency issued by the NWS in Miami, some areas may have received up to 20 inches of rain, which would correspond to at least a 1-in-200-year rainfall event.

Preliminary 24-hour rainfall totals indicate multiple cities and neighborhoods are being impacted. At least 11.09 inches of rain have fallen in Fort Lauderdale, 12.21 inches in Lauderhill and 13.92 inches in Dania Beach as of Wednesday night.