A flash flood warning is in effect until 3:45 p.m. in southeastern San Diego County.
The locations in the warning include but are not limited to Live Oak Springs near Boulevard. The National Weather Service reports that a strong thunderstorm is drifting northwest through the area.
As of about 2:15 p.m., there were more than 100 lightning strikes in the area. So far, no reports from Cal Fire of issues with those lightning strikes.
In the Pine Valley area, some residents reported pea-sized hail according to meteorologist Dagmar Midcap. The heaviest rainfall is happening just north of Campo, according to the NWS.
When one storm collapses, it creates a new one, Midcap explained.
"When the storm dies, it collapses on itself and creates an outflow boundary. When the weight of that storm hits the ground, it has to go somewhere, so it goes in all directions and creates new thunderstorms," Midcap said.
A flash flood warning means a flash flood is imminent or occurring in the warned area. In addition, the NWS has issued a flash flood watch for San Diego's desert and mountain communities through 9 p.m. PT.
On Sunday, August 3, Palomar Mountain, Ramona and Borrego Springs were under a flash flood warning. The excess rain pushed debris and mud onto State Route 78.
On the same day, near Mt. Baldy, One man was killed when his car was was swept into a rain-swollen creek.
If you live or travel in an area under a flash flood warning, get to high ground. Do not cross streams on foot where water is above your ankles. Do not attempt to drive through water-filled areas of unknown depths.
If your vehicle stalls in rising water, get out of it and get to safety. Many people become trapped by trying to move a stalled vehicle.