Major storm dumps snow, closes mountain routes in California

Downtown Portland, Ore., and the Tilikum Crossing Bridge were dusted in snow Sunday, Dec. 26, 2021. Snow is blanketing parts of the Pacific Northwest because of unusually cold temperatures. (Dave Killen /The Oregonian via AP)

Snow had accumulated on a vehicle on Sunday, Dec. 26, 2021. Snow is blanketing parts of the Pacific Northwest because of unusually cold temperatures. (Dave Killen /The Oregonian via AP)

Noah Neighbor pushes his mountain bike up Kite Hill in the snow at Gas Works Park Sunday in Seattle. Snow is blanketing parts of the Pacific Northwest because of unusually cold temperatures. Seattle got between 3 and 5 inches of snow as of Sunday morning. (Ken Lambert /The Seattle Times via AP)

COLFAX, Calif. — A major Christmas weekend storm caused whiteout conditions and closed key highways amid blowing snow in mountains of Northern California and Nevada, with forecasters warning that travel in the Sierra Nevada could be difficult for several days.