From the NOAA website:
FLOOD WATCH NATIONAL WEATHER SERVICE San Diego CA 1247 PM PST Tue Nov 27 2018 San Bernardino County Mountains-Riverside County Mountains- Santa Ana Mountains and Foothills-Orange County Inland Areas- Including the cities of Crestline, Lake Arrowhead, Big Bear City, Big Bear Lake, Running Springs, Wrightwood, Idyllwild-Pine Cove, Santa Ana, Anaheim, Garden Grove, Irvine, Orange, Fullerton, and Mission Viejo 1247 PM PST Tue Nov 27 2018 ...FLASH FLOOD WATCH IN EFFECT FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR RECENT BURN SCAR LOCATIONS... The National Weather Service in San Diego has issued a * Flash Flood Watch for a portion of southwest California... including the following...Orange County Inland Areas... Riverside County Mountains...San Bernardino County Mountains and Santa Ana Mountains and Foothills. * From Thursday morning through Thursday evening. * A Pacific storm will bring rain to Southern California. The rain will begin Wednesday evening, becoming locally heavy on Thursday. Rainfall of around 1/2 inch or more is possible in an hours time, which could lead to debris flows at recent burn scars. The time window of greatest concern is from late Thursday morning through early Thursday evening. * There is the potential of flash flooding and debris flows at recent burn scar locations. This includes the Holy Fire, Cranston Fire, Canyon 1 and 2 Fires, and the Valley Fire burn scars. PRECAUTIONARY/PREPAREDNESS ACTIONS... Heavy rainfall could cause debris flows in recent burn areas according to rainfall thresholds provided by the USGS. Debris flows are extremely dangerous and happen suddenly often with little time to act. It may even not be raining at your location to be impacted by a debris flow. You should monitor the latest forecasts. Heed any advice given from local authorities.
