PEMBROKE PARK, Fla. -- Severe thunderstorms rolled across South Florida on Friday afternoon, knocking out power to thousands and delaying flights at two airports.

Parts of Miami-Dade, Broward and Palm Beach counties were put under severe thunderstorm warnings periodically Friday afternoon as the storms pummeled the area with heavy rain. The National Weather Service issued a flash flood warning for eastern Miami-Dade County until 8:30 p.m. Friday.

Late Friday night, Florida Power & Light said about 8,500 customers in Miami-Dade County had lost their power. In Broward County, 1,400 customers did not have power. On Miami Beach, 2,500 residents lost power.

Crews will work to restore the power once it is safe for them to do so.

Officials at Miami International Airport said the storms had prompted at least 20 delays so far.

As of 4 p.m., 24 flights at Fort Lauderdale-Hollywood International Airport had been delayed. An airport official said the flights were delayed between 30 minutes and an hour.

According to the Florida Highway Patrol Web site, there were 20 active crashes in Miami-Dade County as of 6 p.m.

Local 10's Rob Schmitt reported that traffic was at a standstill on Interstate 395 at 6 p.m. Earlier in the afternoon, Schmitt reported seeing a Cadillac Escalade driving through water that reached its hood in the Brickell area.

Meteorologist Andy Tingler of the National Weather Service said South Beach got hit the worst, with an estimated 7-9 inches of rain in just a few hours Friday afternoon.

The weather service has received reports of flooding and golf-ball-size hail. According to one report, cars were beginning to float down the street. Residents also reported that water was beginning to enter homes.

Besides the rain, excessive lightning had residents seeking shelter. In the area between Miami and Miami Beach, the weather service recorded about 100 lightning strikes in a five-minute period.

The Broward Sheriff's Office said lightning also caused a small house fire in Lauderdale Lakes at about 4:15 p.m. BSO said several people were home at the time, but no one was injured. The fire caused minimal damage, police said.

The Eden Roc hotel on Miami Beach was evacuated due to flooding.