The national weather service in San Diego has issued a flash flood warning for the follow areas: Orange County, San Bernardino County, and Riverside County until 9pm.
At 5:06pm doppler radar indicated heavy rain across the warned area with the heaviest rain moving onshore the Orange County coast which will move east and another area of enhance heavier rain occurring along the coastal mountain slopes of the San Bernardino County mountains and through the Cajon Pass.
Rainfall of 1 to 2 inches has already fallen along the coastal mountain slopes with a half to one inch across Orange County. Flash flooding will likely begin shortly.
In addition, excessive rainfall will likely result in debris flows within and downstream of the 2016 Blue Cut Fire Burn Scar, including railways. The debris flow can consist of rock, mud, vegetation, and other loose materials.
Highway 138 is closed due to 1 to 2 feet of mud covering Lone Pine Rd. Rainfall rate of around 1 inch per hour will occur in the heaviest bands of rain.
Some locations that will likely experience flood include: Anaheim, Santa Ana, Riverside, Irvine, San Bernardino, Fontana, Huntington Beach, Garden Grove, Ontario, Corona, Orange, Fullerton, Costa Mesa, Rialto and Mission Viejo, I-15 through the Cajon Pass, and areas in and around the Blue Cut Fire Burn Scar.
Some precautionary actions suggested are to move to higher ground now and act quickly to protect your life.