MARYSVILLE, Calif. April 6, 2018 – Caltrans is alerting motorists to expect difficult driving conditions as an atmospheric river storm from the Pacific Ocean will bring sustained moderate to heavy rains to California tonight through Saturday evening.

The National Weather Service (NWS) issued a Flood Watch Wednesday for much of northern California and western Nevada. Rains from the initially warm storm are predicted to begin tonight and increase in intensity through Friday and Saturday. A cold front moves in Saturday afternoon with several inches of snow predicted Saturday through Sunday morning for mountain areas above 5,000 feet.

The storm’s significant precipitation may combine with snowmelt to to bring an enhanced flooding potential for rivers, creeks, streams and urban areas, particularly areas with poor drainage or a history of flooding. Excessive rainfall may also generate rock and mud slides in steep terrain.

Donner and Echo Summit passes are expected receive snowfall as the cold front moves in Saturday. Motorists traveling on Interstate 80 (I-80), U.S. Highway 50 and other mountain highways should expect chain controls. To assist motorists, Caltrans permitted and trained chain installers will be available on I-80 and Highway 50 and can be identified by a reflective sign with their bib number.

Severe weather is expected to slow motorists, resulting in traffic congestion. Heavy or sustained rainfall can result in water pooling on roadways, reducing tire traction, especially at high vehicle speeds, resulting in a loss of driver control. Motorist are encouraged to slow down.

Additionally, poor drainage or overflowing streams or rivers may flow onto roadways. Motorists are strongly advised to “Turn Around, Don’t Drown” when they observe water covering the roadway – the roadway underneath may be damaged and water may be flowing strongly enough to sweep vehicles off the roadway. Please observe all road closed signage.

Visit Caltrans’ “QuickMap” for current road conditions and chain requirements at A mobile version is also available through the iPhone App Store or in Google Play. Motorists also can use the California Highway Information Network automated phone service by calling 1-800-427-ROAD (7623).

Follow Caltrans District 3 on Twitter @CaltransDist3 and Facebook to receive the latest information about current roadway conditions. For forecast information, visit the National Weather Service website.

Caltrans crews will be working around the clock to keep the roadways open and clear. Motorists are urged to be “Be Work Zone Alert” and to “Slow for the Cone Zone.”