Sierra Prepares To Be Buried Under Several Feet Of Snow From Atmospheric River

TRUCKEE (CBS SF) -- While a mid-week atmospheric river will bring pounding rains to the San Francisco Bay Area, its wintery blast will bury the Sierra under as much as 6 feet of new snow, forecasters predicted Sunday.

Light snow showers were predicted for Sunday as a weaker weather system rolls through the region and up to 6 inches could fall, but it is the arrival of potent plume of moisture by early Wednesday that is projected to be the main event.

"Multiple feet of snow are expected as an atmospheric river moisture source pushes into the Sierra," National Weather Service forecasters warned. "While 3-4 feet of snow is what looking most favorable along the Sierra crest (1-3 feet in the lower Sierra basins), there is potential on the high end to reach 5-6 feet along the crest mainly where the atmospheric river plume pivots back northward."

The weather service has issued winter weather advisory that will certainly be raised to a warning by Monday or Tuesday. Travel in the high passes of Highway 50 and I-80 will likely come to a halt and chains will be required through the upcoming weekend.

"If you are planning to travel through the area, plan wisely!!," CHP Truckee warned on its Facebook page. "Be prepared for MAJOR travel delays, for chain control, and for possible road closures. Notice the possibility of 7 feet of snow."

Strong wind gusts will also trigger drifting snow, blinding driving conditions and a heightening of a threat of avalanches.

While the San Francisco Bay Area has been locked into severe drought conditions, the Sierra has seen some snowfall this year. The Dec. 30th snow survey by the California Department of Water Resources -- the first of the winter season -- determined that the snowpack was 93% of average to date.

"Today's survey is a little higher than what we've been seeing based on automated snow measurement based on 130 sensors statewide," said Sean de Guzman, chief of snow surveys and water supply forecasting, at the time of the survey.

Squaw Valley officials reported that before Sunday's storm they have had 108 inches fall this season at 8,000 feet and above. Meanwhile, Heavenly located in South Lake Tahoe has seen 72 inches of snowfall in total this season.