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

Date: Fri, 23 Mar 2018 15:37:47 EDT

Summary: An atmospheric river (AR) that brought precipitation to nearly all parts of California during the past few days, is moving out of the region today.

The largest amount of rainfall from this storm event occurred along the Central Coast, an area that received 8-12 inches of rain over the past 72 hours, according to the Center for Western Weather and Water Extremes. A USGS precipitation gage near Filmore CA (343120118533301) located along the eastern margin of the Thomas Fire burn scar recorded 4.58 inches of rain over the past 72 hours. Late Thursday, evacuation orders were lifted for recent burn areas in Santa Barbara, Ventura, and Los Angeles Counties.

Yesterday, four USGS gages in CA with NWS defined flood stages exceeded minor or moderate flood levels, according to USGS Water Watch. Forty four real-time USGS streamgages in CA had flows above the 90th percentile for this day of year; and 20 of those streamgages had the highest streamflow ever for that date. One site in foothills of the Sierra Nevada exceeded the historical Peak – site 11284400 Big Creek with 48 years of record. USGS flood crews made approximately 30 high-flow measurements yesterday for streamflow verification.

Today, many streams in CA are receding, and crews are deployed for streamflow rating verification measurements. The USGS California Water Science Center (CAWSC) currently has 15 crews deployed from the following service areas: Santa Maria, CA (3 crews); Santa Cruz, CA (5 crews); Poway, CA (2 crews); Ukiah, CA (1 crews); Redlands, CA (2 crews), and Sacramento (2 crew). No crews are expected to deploy over the weekend. Currently, all streamgages are transmitting data. No equipment damage or safety issues have been reported.