HELENA, Mont. (AP) - Temperatures across the western half of the nation are plunging as much as 40 degrees below normal as an Arctic cold-air mass moves south.
A storm system that brought up to 2 feet of snow and bitter cold to the Rockies and Northern Plains was moving south Tuesday.
The cold air was expected to threaten citrus crops in California and move into Texas by the end of the week.
Snow and ice created hazardous driving conditions throughout the West. Montana authorities say 21-year-old Chelsea Stanfield was driving too fast for the conditions when she died in a four-vehicle crash near Great Falls Monday.
Portions of interstates in Wyoming and Oregon were closed because of the snow and ice.
Officials issued travel advisories and warned people to protect themselves against frostbite.