PROJECT ALERT NOTICE (CA) California experiencing a wave of AR storms—Continued, Day 7

Date: Tue, 10 Jan 2017 17:33:40 EST

Summary: Multiple atmospheric rivers continue to bring heavy rainfall and snow to many parts of California this week.

Yesterday, streamflow in many streams increased and peaked in response to heavy rainfall on Sunday. Over 65 percent of USGS streamgages in CA reported streamflows yesterday that were more than 90 percent above normal flow for this time of year. Crews from the California Water Science Center made over 40 discharge measurements at streamgage locations across California. The highest streamflow measurement made by crews related to this storm event and, incidentally, the highest recorded measurement for the period of record, was 79,100 cfs for the Yuba River near Marysville, CA (11421000).

Streams are currently receding but are expected to rise and peak again tomorrow in response to rainfall occurring today across most of California. Today, southern California will receive light rainfall, and central and northern California will receive moderate to heavy rainfall, with snow accumulations at higher elevations. Flood warnings and watches are in effect for the North Coast and Central Valley, and blizzard and winter storm warnings are in effect for the Sierra Nevada. For the rest of the week, light to moderate precipitation is expected to continue across the region through Thursday. This precipitation, which adds to previous accumulations of rain and snow from last week’s storms, will increase the potential for flash floods, landslides, and avalanches. Currently, streamflow at numerous sites across the State are above the 95th percentile, with many of those streams predicted to peak and exceed flood or monitor stage today and on Wednesday.

The California Water Science Center (CAWSC) currently has 17 crews responding to this event from field office in the following service areas: Ukiah, CA (3); Redding, CA (2); Eureka, CA (1); Santa Cruz, CA (5); Truckee, CA (1); and Sacramento, CA (3). More crews are planned to deploy tomorrow.

No other streamgages have experienced damage or interruptions in data transmissions, besides the streamgages mentioned in previous Project Alerts for this event. No safety issues have occurred during this series of storms and all staff have followed USGS field reporting and safety protocols. Updates will continue to be provided during the course of this event.