US: Rain increases possibility of flooding, mudslides in California Dec. 4-5 /update 2

Event

A large storm system is forecast to move across California beginning the evening (local time) of Tuesday, December 4, and into Wednesday, December 5. Moderate to heavy rain is expected along the coast, from Santa Cruz to San Diego, including the Los Angeles metropolitan area, with lighter rain falling across most of the remainder of the state. Meteorologists raised concerns over flooding, mudslides, and debris flows in burn scar areas, particularly near the Thomas and Woolsey fire areas (Ventura, Los Angeles, and Santa Barbara counties). Flooding, mudslides, debris flow, along with associated infrastructure damage and transportation disruptions are possible in the abovementioned areas. Mudslides are most likely in canyons and low-lying areas. Other weather-related traffic congestion and transportation disruptions are possible across the region.

Context

California regularly experiences wildfires from May through November and this year had some of the largest and deadliest fires in the state's recorded history. As of November 11, 7579 fires have burned roughly 675,000 hectares (1,668,000 acres).

Due to a lack of living vegetation and the presence of ash, mudslides and debris flows are common during rainstorms following the wildfire season.

Advice

Individuals in California are advised to monitor local weather reports, anticipate transportation disruptions, adhere to instructions (e.g. evacuation notices and road closures) issued by local authorities, and avoid areas downhill from burn scars.