PROJECT ALERT NOTICE (CA) Flooding continues for California - Day 9

Date: Wed, 15 Feb 2017 18:05:07 EST

Summary: Flooding continues in California as another series of AR storms brings more rain to the region.

Another series of atmospheric river storms will bring rain and snow to California begin today and continuing possibly through the end of next week (Feb 23). The north coast of California will experience moderate rainfall today, with precipitation expected for all of California on Thursday and Friday. Parts of California could receive more than 8 inches of rain over the next 6 days alone, with the storm on Friday expected to bring as much as 4 inches of rain to Santa Barbara and Los Angeles. The National Weather Service (NWS) has issued flash flood warnings for much of southern California for Friday, Feb 17. Major flooding is expected, along with increased potential for flash floods, landslides, and debris flows, especially in urban or recent wildfire burn areas.

Today, north coast and north central counties remain under flood warning or flood watch. The NOAA/NWS California Nevada River Forecast Center reports many California rivers remain above flood (10 gages) or monitor (26 gages) stage today, including 13 gage locations along the Sacramento River, 4 gages on the San Joaquin River, and 2 gages on the Feather River. The San Joaquin River at Vernalis, CA (11303500) is currently above flood stage but is expected to exceed danger stage on Monday, February 20.

The California Water Science Center (CAWSC) has 3 crew responding to this event today from the Redding, CA (1), Ukiah, CA (1), and Sacramento, CA (1) service areas.

Crews from Redding and Ukiah are deploying 25 water-level monitors along the Feather River floodplain to collect data that may be used to advance and refine hydrologic models. These data are collected as part of a short-term network that will be used by the USGS to monitor the watershed for the remainder of California's rainy season. The USGS is coordinating this work with officials from the California Department of Water Resources (DWR). Although the mandatory evacuation for the Oroville, CA area has been lifted, an evacuation warning remains in effect and the USGS is following standard safety protocols while working in the area.

A USGS crew from Sacramento is performing high-flow measurements today at two USGS streamgages on the San Joaquin River that are used for flood forecasting: 11274000, San Joaquin River near Newman, CA; and 11303500, San Joaquin River near Vernalis, CA. These measurements were requested by DWR and the NWS California Nevada River Forecast Center to refine the streamflow ratings for these sites at higher flows. The San Joaquin River at Vernalis, CA (11303500) is expected to exceed danger stage on Monday, February 20. The designation of danger stage is used for flood control projects where an elevated stage poses an extreme danger with threat of hazard to life and property in the event of a levee failure.

No safety issues have occurred during this series of storms and all staff have followed USGS field reporting and safety protocols. Flood response crews are expected to deploy tomorrow and into the weekend. Updates will continue to be provided during the course of this event.