PROJECT ALERT NOTICE (CA) CAWSC storm response

Date: Thu, 13 Feb 2025 15:11:05 EST

Summary: CAWSC field crews measuring elevated flows after atmospheric river event

The initial wave of an atmospheric river is causing high flows and high wind gusts in the area approximately from San Francisco through southern California. When this system arrived, the ground was saturated and streamflows were still elevated due to precipitation early last week. The atmospheric river is forecast to bring precipitation to most of the state through tomorrow.

87 streamgages are at elevated flows, with 1 above moderate flood stage, 2 above minor flood stage, and 4 above action stage. Areas with USGS streamgages at higher flows include the Trinity R basin, Truckee through Markleeville, Santa Rosa, Hayward through Santa Cruz, Goleta, Los Angeles, and San Bernardino. 22 field crews consisting of 36 staff are in the field today. Most crews are measuring streamflows and tending to streamgage equipment, while one crew is installing a Rapid-Deployment Gage (RDG).

There is much concern about the rainfall causing high flows, debris flows, mudslides, and landslides from the recent burn areas into populated areas of Los Angeles. Today, a crew is installing a RDG in a high-risk area of Topanga Canyon, entirely burned by the Palisades Fire in January. Staff are coordinating the RDG installation with the USACE LA District.

No periods of record extremes at any of the USGS streamgages are anticipated today.