"My windshield wipers couldn't move fast enough. It was raining pretty hard. There was just so much water all over. I couldn't tell what was going on," said Eric McGinley, whose car got caught up in the flash-flooding near Gilman Springs.
McGinley said his visibility was so poor that he didn't realize he was driving into a massive mudslide. Firefighters say McGinley wasn't the only driver who was caught off guard by the powerful storm.
PHOTOS: Rain soaks Southern California
"At 1:30 this morning, approximately, we got our first call about a rescue. Since then, we've rescued 40 people out of their vehicles," said Capt. Lucas Spelman with the Riverside County Fire Department.
Eight residents were evacuated from their homes as a precautionary measure in the 20500 block of Gilman Springs Road due to the threat of mud and debris flow. No injuries were reported.
Heavy flooding also displaced two families from two apartments on the 41900 block of Acacia Avenue in Hemet.
Tammy Gatavetsky's home was flooded, and all her valuables were damaged.
"We just finished paying our rent and all our bills. We have like $97 for the month to live on," said Gatavetsky.
Directly across the street, Sammy Ramirez was leaving for work when his car stalled in a driveway.
"It was terrible dude. It's never been this bad," said Ramirez.
In San Jacinto, firefighters rescued three people trapped in a vehicle in water on Soboba Road near Lake Park Drive; the occupants of the vehicle were not injured.
A flash-flood warning for western Riverside County expired at 8:30 a.m. The rain moved southeast and was out of most areas by late Thursday morning.