A late season storm blowing in from the north triggered a winter weather advisory beginning late Friday in the Sierra, where several inches of snow is expected at Lake Tahoe and up to a foot in upper elevations.
The advisory is effective from 11 p.m. Friday until 2 p.m. Saturday.
The National Weather Service also issued a lake wind advisory effective for the Sierra's eastern front until 8 p.m. Friday. Winds gusting to 25 mph are possible at Lake Tahoe and Pyramid Lake, where wave heights could reach 3 feet.
The weather service says tire chains will likely be required on Interstate 80 over Donner Pass between Reno and Sacramento, as well as Carson Pass, Echo Summit and Lassen National Park.
The cold, low pressure system is forecast to drop out of the Gulf of Alaska and make its way across Northern California, with temperatures dropping into the low 20s at Tahoe and low 30s around Reno.
“Things changed drastically,” service spokeswoman Jessica Kielhorn said.
Six to 12 inches of snow is forecast at elevations between 6,500 and 7,000 feet. The precipitation should be limited to rain showers in the valleys, including areas around Reno and Carson City.
The weather service said snow will create slick, icy roads, and it urged Sierra travelers to carry tire chains and expect travel delays.
The late April storm comes during the driest of four straight years of drought. The Truckee River basin's snowpack Thursday was measured at 12 percent of normal for the date. The Lake Tahoe basin snowpack was at zero.
The dry conditions have prompted organizers of the 12th annual Reno River Festival next month to cancel the kayaking competitions typically run on the Truckee River during the celebration, the Reno Gazette-Journal (http://tinyurl.com/nrjhtcf ) reported.