Tropical Storm Eta has caused chaos in Florida's already flooded streets as it made landfall late on Sunday night on Lower Matecumbe Key.
Beaches and coronavirus testing sites were closed, public transportation shut down and some evacuations were put in place early Monday.
Having left many dead and over 100 missing in Mexico and Central America, Eta posed an enormous threat to South Florida, an area already drenched from more than 14 inches (350 millimeters) of rain last month. Forecasters said the storm could dump an additional 6 to 12 inches (150 to 300 millimeters).
Miami-Dade County Mayor Carlos Gimenez said he was in frequent contact with county water officials about the struggle to drain the flooded waters, which has stalled vehicles, whitewashed some intersections and even crept into some homes.
On Sunday night, authorities in Lauderhill, Florida, responded to a report of a car that had driven into a canal. Photos taken by fire units on the scene about 30 miles (48 kilometres) north of Miami showed rescuers searching high waters near a parking lot.
Firefighters pulled one person from a car and took the patient to a hospital in critical condition, according to a statement from Lauderhill Fire.
Responders were continuing to search for others.
The U.S. National Hurricane Center in Miami declared hurricane and storm surge warnings for the Keys from Ocean Reef to the Dry Tortugas, including Florida Bay.
Eta had maximum sustained winds of 65 mph (100 kph) early Monday and was centered around 25 miles (40 kilometres) northwest of Marathon, Florida, and 40 miles (80 kilometres) northeast of Key West.
On the forecast track, Eta was expected to move out into the southeastern Gulf of Mexico and intensify into a hurricane late Monday or Tuesday.