Chains or snow tires are required this across the mountain passes in the Sierra, and forecasters say travel will only get worse before it gets better.
A winter storm warning is in effect for the Lake Tahoe region, where forecasters say more than a foot of new snow is expected above 7,000 feet.
In the Reno-Carson City area, mild temperatures ahead of the storm will drop into the 30s, lowering snow levels to the valley floors during the day.
Western Nevada is under a snow advisory through 7 pm.
Central and eastern Nevada are under a winter storm warning.