Snow and rain created havoc Wednesday over the Sierra Nevada as forecasters warned of a stronger storm coming this weekend to much of Northern California, including the Sacramento Valley.
The National Weather Service issued a flood watch effective Saturday through Monday for much of Northern California, including the Sacramento Valley and west slope of the Sierra. An “atmospheric river” likely will produce a prolonged period of occasionally intense rainfall with snow levels above the 7,000 to 8,000 foot elevations in amounts not seen since December 2005, officials said.
In anticipation of the Sierra runoff, the Bureau of Reclamation announced plans to incrementally increase releases into the American River below Nimbus Dam from 3,500 cubic feet per second to 15,000 cfs Thursday. Adjustments will be made as necessary and may occur on short notice, the bureau warned.
Officials advised people along the lower American River downstream of Folsom Dam to the confluence of the American and Sacramento rivers to expect river levels to rise and to take precautions.
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Conditions Wednesday caused Caltrans to shut down eastbound Interstate 80 in the Sierra Nevada. A Caltrans camera showed heavy snow and traffic backed up on the highway, where eastbound vehicles were being detoured in Colfax. On Highway 50, traffic was being held at Echo Summit for avalanche control. Westbound traffic on I-80 was being held at the Nevada state line and Truckee.
“We have a tremendous amount of snow and we have a tremendous amount of traffic,” said Dave Wood, Caltrans maintenance superintendent for the Donner Pass-Sutter/Sierra Region.
Rain falling below 6,000 feet kept crews busy clearing drains to prevent roadway flooding, he said, while crews above 6,000 feet were dealing with snow, fog and motorists traveling either too fast or too slow for conditions, resulting in spin-outs and collisions.
Many motorists, he said, weren’t prepared to travel in the storm.
“Trying to learn to drive in snow today is like trying to teach your kid to hit a fastball in the World Series,” Wood said.
Rain continued in Sacramento throughout the day Wednesday. In anticipation of high water in many areas, the Sacramento County Department of Regional Parks announced Wednesday that it had closed areas of the American and Dry Creek parkways. County park rangers were warning park visitors of the rising water levels. The Sacramento County Sheriff’s Department said residents near waterways may hear public address announcements from the ground and air advising people near shorelines of area waterways to move to higher ground.
As of about 5:30 p.m. Wednesday, downtown Sacramento had recorded 0.76 inches of rain for the 24-hour period, with 0.44 inches and 0.73 inches reported at Sacramento International and Sacramento Executive airports, respectively, said Johnnie Powell, a meteorologist with the National Weather Service. Roseville had received 0.95 inches, while 0.91 inches was reported in Folsom and 1.73 inches in Auburn.
The Sacramento area should start drying out by about noon Thursday and remain dry Friday. But the storm forecast for the weekend is expected to deliver twice the amount of rain as the last storm. Powell said 2 to 3 inches – about an inch per day – is forecast for Saturday through Monday.
The weekend storm will be a warm one, with snow levels rising to about 7,000 feet, above the passes, by late Saturday or Sunday morning. That means rain, rather than snow at pass levels and below.
“We could lose all that snow,” Powell said. “It depends on how much rain we get.”
Powell advised people to clean storm drains and to have sand bags on hand if their property is prone to flooding.
The coming storm, he said, has the potential to do damage.