The most powerful Pacific storm of the season is forecast to bring up to 10 feet of snow into the Sierra Nevada by the weekend. Blizzard conditions have forced residents to take shelter and prompted at least two Lake Tahoe ski resorts to close Friday. Yosemite National Park also plans to close through at least Sunday. The storm began barreling into the region on Thursday, with the biggest effects expected to close major highways and trigger power outages Friday afternoon into Saturday. A blizzard warning through Sunday morning covers a 300-mile stretch, from north of Lake Tahoe to south of Yosemite National Park.