A colossal storm is poised to barrel across the northern Sierra Nevada Wednesday evening, with high winds whipping heavy falling snow and creating blizzard conditions.

The National Weather Service advised against all travel in the mountain range straddling California and Nevada through Thursday.

"I would call this storm extremely dangerous," said Karleisa Rogacheski, a meteorologist with the NWS Sacramento office. "During whiteout conditions, it's going to be near-impossible to drive."

The NWS has issued a winter storm warning for elevations between 5,500 feet and 6,500 and a blizzard warning for elevations above 7,o00 feet, where conditions will be "potentially life-threatening" with "zero visibility in whiteout conditions."

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"It's a blizzard when gusts over 35 mph are blowing snow and reducing visibility to a quarter mile or less for a period that lasts three hours or more," explained Rogacheski. "It's definitely looking like that late tonight."

Isolated wind gusts for valleys could reach up to 70 mph and up to 110 mph on mountain tops. Snowfall will be steady and "kind of gnarly," said Rogacheski.

Between Wednesday and Thursday nights, Donner Pass is expected to record 48 inches to 60 inches of snow, Echo Pass 24 inches to 30 inches, Carson and Sonora Pass 60 inches to 80 inches and Tioga Pass 36 inches to 48 inches.

Rogacheski expects the first window for safe travel in the Sierra to arrive Friday morning, when skies will clear. Dry conditions are also forecast for Saturday, and the potential for snow returns to the forecast Sunday.

Send photos, videos and stories from the storm to SFGATE news producer Amy Graff at agraff@sfchronicle.com