J Pat Carter / AP Andre Francois wades through knee deep flood water in Boynton Beach, Fla., on Friday to get back to his house.

A torrential downpour lashed Florida's Palm Beach County before dawn Friday, shuttering schools, flooding an interstate and causing at least two deaths.

More than 22 inches of rain fell on Boynton Beach over a 24-hour period, according to the National Weather Service. The Sun Sentinel newspaper said the most rain was around Interstate 95 and Gateway Boulevard, while between 12 and 18 inches fell over just a few hours in Lantana and Delray Beach.

"An incredible rainfall rate," said Robert Molleda, a meteorologist with the NWS. "There is no way we could forecast that much rain in that short a time."

The first of the two deaths occurred just after 7 a.m. Friday in West Delray: Elsa Marquez, 56, steered her Toyota Rav 4 through a flooded intersection at Heritage Park and Via Flora into a lake, and her vehicle quickly sank.

Elsewhere in Delray Beach, a man died after drowning in a flooded ditch, according to NBC affiliate WPTV in West Palm Beach.

Several roads were closed and water gushed into homes and businesses, according to the National Weather Service in Miami. The rushing floodwater also forced the closure of Palm Beach County schools Friday, the Weather Channel reported.