US: Rain across California prompts concern of mudslides November 28-29 /update 1

Event

A storm system will bring heavy rain and snow to California beginning Wednesday, November 28, and continuing into Thursday, November 29. The US National Weather Service (NWS) issued warnings over the threat of debris flows and mudslides in and below burn scar areas, notably for the Camp (Butte county), Carr, Delta, Hirz (Shasta county), Mendocino complex (Lake, Colusa, Mendocino, and Glenn counties), and Ferguson fires (Mariposa county). Flash flood watches are in effect for much of northern and central California from Wednesday evening (local time) to Thursday morning and a flash flood warning, with reports of flooding and debris flows, is in effect in Mariposa county until 16:30 on Wednesday.

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 mudslides.

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.