Bay City News Service—The Napa and Russian rivers are expected to reach flood stage Sunday and Monday following days of heavy rain, according to the National Weather Service.
The third storm in recent days was expected to arrive Saturday evening and continue into Sunday, bringing an additional three to seven inches of rain in higher elevations. The North Bay is expected to see the heaviest rains, according to the weather service forecast.
For Piedmont, the National Weather Service was predicting heavy rain Saturday night and today, with an overnight low of 57 degrees and a high today of 59 degrees. The NWS's Oakland North station, in the Oakland Hills, showed .91 inches of rain in the 24-hour period ending at 9 p.m. Saturday.
The Napa River is expected to reach flood stage in St. Helena around noon on Sunday, with water at heights of 15.9 feet, and crest around 3 p.m. at 17.8 feet, the National Weather Service said in its most recent forecast.
In Napa it will reach flood stage around 1 p.m., with water at heights of 25.2 feet, and crest around 4 p.m. at 26.7 feet. Napa city officials said the flooding is expected to occur in a "largely agricultural and minimally developed area" around Oak Knoll Avenue, about five miles north of the city itself.
The Russian River will reach flood stage in Guerneville around 2 a.m. Monday morning, with water at 31.7 feet, and crest around noon at 35 feet, the forecast said.
The weather service has also issued flash flood and mudslide warnings for the entire Bay Area, but the North Bay and the Santa Cruz mountains are expected to at particularly high risk.
Urban flooding is also likely throughout the Bay Area. Many Bay Area communities are offering sandbags to residents hoping to prepare for flooding, and the California Highway Patrol is warning drivers to expect hazardous conditions.
The California Geological Survey issued a warning this week about landslides and mudslides, noting that they can occur on any sloped surface and are a particular risk during periods of heavy rain.
Residents on slopes or living at the bottom of a slope should check for fresh cracks in the soil, areas of bare soil and water or mud streaming downhill.
While large landslides are slow, fast-moving debris flows, often called mudslides, move quickly and can be hard to escape.
"If your residence is on or beneath a slope, the most important thing you can do to protect your safety is to avoid sleeping in lower-floor bedrooms facing the slope during periods of heavy rain," said Chris Wills, who heads the CGS' landslide mapping program.
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