Pacific Gas & Electric Co. says a rock slide broke a major transmission pole that serves Yosemite and El Portal, cutting power to 585 customers there. PG&E is flying in a replacement since snow is blocking vehicle access to the location.
Park officials said they're using backup generator power that will last about a week. Most rooms in hotels and other buildings, however, have no heat or hot water.
All access roads remained closed to traffic Tuesday morning, but one lane of Highway 120 was open for visitors wanting to leave the park.
The Associated Press contributed to this report.