The Cheyenne Office of the National Weather Service is warning people that travel conditions in much of Wyoming are likely to become ''extremely difficult or impossible" starting this evening.

The agency posted this statement on its website on Friday morning:

"Blizzard and Winter Storm Warnings have been issued for much of Carbon County, as well as areas along and north of a line from Douglas to Alliance. High Wind Warnings have been issued for the remainder of the area. All headlines are valid from 6 PM this evening until 5 AM MST Sunday. However, ahead of the snow and wind much of the area can expect the potential for freezing drizzle. There will even be a chance for a brief period of freezing rain and minor ice accumulations in the northern Nebraska Panhandle this evening. Snow will be heaviest over western and northern areas, though residents in northern Platte and Goshen Counties should be mindful of an enhanced risk for blizzard conditions near the Converse/Niobrara county line as snowfall totals will increase dramatically as you head north. Wind gusts in excess of 65 MPH are expected across all of southeast Wyoming and the western Nebraska Panhandle. Whiteout conditions are likely where Blizzard Warnings have been posted, resulting in severe travel impacts with travel likely to become extremely dangerous or impossible overnight through Saturday. While less snow is expected in the High Wind Warning area, there is also the possibility that existing snow pack may cause problems with low visibilities and sheeting of ice on roadways. AVOID TRAVEL if possible tonight and tomorrow! Always carry a winter survival kit in your vehicle. "