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

Date: Wed, 21 Mar 2018 15:20:45 EDT

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

The strongest part of this AR storm track is expected to bring heavy rainfall today and tomorrow to parts of southern California and the Central Coast, with up to 5 feet of snow expected for high elevation areas of the Sierra Nevada. National Weather Service (NWS) advisories in effect through Friday include a winter storm warning for the Sierra Nevada, and multiple flash flood watches for areas of southern California and the foothills of the Sierra Nevada. In southern California, mandatory evacuations have been issued for Santa Barbara, Ventura, and Los Angeles counties, with particular focus on recent burn areas. According to the NWS, areas of Santa Barbara and Ventura County could receive 6 to 10 inches of rainfall over the next 36 hour, which includes areas burned by the 2017 Thomas Fire - California largest fire in recent history.

Streams in central and southern California are just beginning to rise in response to this storm event, with streamflow expected to peak Thursday morning or late afternoon. Today, the California Water Science Center (CAWSC) has 5 crews deployed from the Santa Maria, CA service area to measure base-flow, first-flow, and rising-limb conditions in select southern California streams. More CAWSC crews are expected to deploy tomorrow in response to the peak streamflows expected. Staff have been reminded to follow established safety and communication protocols, but most especially when working in burn areas or in remote locations.

The CAWSC has been in contact with several cooperators in Santa Barbara County to discuss expected flows and streamgage access options in the event of road closures.

No data transmission or equipment damages have been resulted from this storm event.