USA – Winter Storm Dumps 230mm of Rain in California

A winter storm has dumped more than 9 inches / 228.6 mm of rain in parts of California, causing flooding and mudslides.

Flash flood watches were in effect for much of the Bay Area, with some rivers expected to reach moderate to major flood stage. Flash flood watches were also issued further south for recent burn areas and parts of Los Angeles County. Mandatory evacuation orders have been issued for residents of Lake Elsinore. Voluntary evacuation orders were issued for other burn sites.

Winds and Snow

The storms also brought strong winds and heavy snow. National Weather Service (NWS) San Francisco said winds of up to 75 mph were recorded in Mt St Helena.

Strong winds caused delays and cancellations at San Francisco International Airport. Strong wind damaged power lines and poles, leaving more than 80,000 customers without power. Wind damage and rockfalls left several roads closed and one person suffered minor injuries in Monterey County after a tree fell onto a home.

Snowfall of over 8 feet (2.4 meters) was expected in some areas of the Sierra Nevada mountains.

Rainfall and Flooding

The heavy rain is the result of warmer atmospheric moisture known as the “Pineapple Express” which is pushing an atmospheric river over California.

NWS San Francisco said that the Venado recorded the highest rainfall totals of 9.04 inches / 229.67mm in 36 hours to late 13 February, 2019.

San Francisco meanwhile recorded its 5th wettest February day, with 2.49 inches / 63.25mm falling in 24 hours to 13 February.

36 hour rainfall totals – NWS San Francisco

Further south, NWS Los Angeles said Rocky Butte in San Luis Obispo County recorded 1.81 inches of rain in 24 hours to 13 February. Avalon Inland in L.A. County recorded 0.98 inches.

Flooding was reported in the Bay Area where roads have been closed. Local emergency services have carried out numerous high water rescues, mostly drivers stranded in vehicles.

Flood warnings were issued for several river, including the Guadalupe and Russian, as levels increased. Willow Brook at Penngrove Park had exceeded major flood stage as of 14 February.

Willow Brook at Penngrove Park had exceeded major flood stage. Image: NWS