The flooding shut down the city's airport, rail services, and inundated emergency responders.
Broward County Sheriff's Office was overwhelmed with 911 calls, advising stranded residents to call tow truck companies instead.
The unexpected rainfall came as a surprise to many locals despite Florida being accustomed to daily torrents of rain and hurricanes.
Fort Lauderdale is under a local state of emergency, signed by Mayor Dean J. Trantalis.
Broward County public schools shut down on Thursday due to heavy and concentrated rain.
Fort Lauderdale-Hollywood International Airport suspended flights and ground transportation entrances/exits were impassable.
Many passengers were stranded at the airport, with Stephanie Spiegel describing the rain as "biblical proportions."
Gianey's home was flooded, and he had to search for a safe and dry location to sleep with his three dogs.
The torrential rain took Gianey by surprise, likely damaging parts of his home, and the floodwaters reached his Toyota 4Runner's hood.