Winter storm warnings and winter weather advisories were posted Sunday evening for much of the southern half of the state.
The Montana Department of Transportation reported snow and slick conditions on most state roads and highways, including Interstates 15, 90 and 94. There were several incidents of trucks jackknifing and closing down highways until they could be cleared on Sunday.
In addition to the snow, bitter cold temperatures and wind chills were expected to continue Sunday night and Monday.
Wind chill advisories were posted for a large part of the state, warning of wind chills of as much as 30 below zero (minus 34 Celsius).