PROJECT ALERT NOTICE (CA) Major AR storm brings flooding to CA - continued

Date: Thu, 22 Mar 2018 14:42:49 EDT

Summary: A large atmospheric river brings precipitation to nearly all parts of California today through Saturday, in what is likely to be the strongest storm of the year.

Today, the strongest part of this AR storm track is expected to bring heavy rainfall to parts of southern California and the Central Coast. Over the course of this storm, the Sierra Nevada could receive as much as 5 feet of snow, with 5 and 8 inches of total rainfall likely for the Central Coast and Sierra Nevada foothills, respectively. National Weather Service (NWS) advisories in effect through Friday include multiple winter storm warnings for the Sierra Nevada, and multiple flash flood warnings for areas of southern California and the Sierra Nevada foothills. In southern California, workers and residents are still under mandatory evacuation in recent burn areas of Santa Barbara, Ventura, and Los Angeles Counties. Mud and rock slides have caused road closures, mainly along the central coast, including Highway 1 near Big Sur. County officials and emergency responders remain on alert for potential flash flooding, landslides, and mud/debris flows following the heavy rainfall expected today.

Many streams in CA are currently rising in response to this event with peak streamflows expected later today or tomorrow. The NWS California Nevada River Forecast Center predicts that most flood forecast points in California will remain below critical flood stage in response to this storm event but local flooding is likely. Currently, 11 flood forecast points in CA are predicted to have streamflows above NWS flood monitor stage, and 2 locations are predicted to exceed the NWS flood stage. Reports generated from U.S. Geological Survey (USGS) Water Watch for California show 20 real-time USGS streamgages in CA have flows above the 90th percentile for this day of year; 5 of those streamgages are experiencing the highest streamflow ever for this date.

The USGS California Water Science Center (CAWSC) currently has 27 crews deployed from the following service areas: Santa Maria, CA (6 crews); Redding, CA (2 crews); Santa Cruz, CA (3 crews); Poway, CA (4 crews); Ukiah, CA (3 crews); Truckee, CA (5 crews), and Sacramento (4 crew). Additional crews are expected to deploy tomorrow, as needed, but flood work is currently not planned for the weekend. Currently, all streamgages are transmitting data. No equipment damage or safety issues have been reported.

This morning, a USGS crew onsite at streamgage 11147500, Salinas River at Paso Robles, CA assisted with the swift water rescue of a man who was trapped in a tent that had been washed into the rising river.