* Blizzard warnings issued for Plains, western Midwest
* Part of I-70 in Colorado closed by blowing snow
* Many areas to have a White Christmas
CHICAGO, Dec 19 (Reuters) - The first major winter storm of the season, which started Tuesday in the Rocky mountains, could dump more than a foot of snow in some areas of the central Plains late Wednesday, the National Weather Service said.
"It has evolved into a full-fledged blizzard around the Colorado, Nebraska and Kansas border area..." said Alex Sosnowski, meteorologist for Accuweather.com. "It's a pretty nasty storm."
He said the wind attached to the storm is also blowing dust in the West Texas area, causing traffic accidents.
In Colorado, Interstate 70 was closed east of Denver to the Kansas state line due to high winds blowing snow into drifts and reducing visibility, said Mindy Crane, spokeswoman for the Colorado Department of Transportation.
Several other roads in eastern Colorado were closed because of the blizzard conditions, she said.
Crane also said a stretch of Interstate 70 in the mountains near the ski resort of Vail was closed temporarily on Wednesday so crews could do some work to prevent avalanches.
The storm marks a major change from the mild December so far in most of the nation, Sosnowski said. This means many parts of the country could see a White Christmas. More storms are expected in the middle of next week.
Blizzard warnings have been issued Wednesday in parts of Colorado, Nebraska, Kansas, Iowa, Missouri, Minnesota, Wisconsin and Michigan, meteorologists said.
The heaviest snow is falling at a rate of up to an inch per hour in parts of Nebraska, Kansas and Colorado. The worst of the blizzard is expected to hit communities from Omaha, Nebraska, to Green Bay, Wisconsin, Wednesday night into late Thursday, according to Accuweather.com.
In Chicago, the storm is expected to begin as rain and later change to snow Thursday, Sosnowski said.
Heavy snow and high winds were expected anywhere from the central plains into the Midwest/Great Lakes regions through much of the day Thursday, the National Weather Service said. Hazardous travel conditions were expected through Thursday and into early Friday.
Moisture off the Gulf of Mexico is expected to cause rain in the lower Mississippi River Valley Thursday, pushing east into the southeastern states Friday.
In the West, a system along the Pacific coast will bring scattered snow and rain showers into the northwestern states, according to the weather service. Over a foot of snow is expected in the higher elevations of the Washington Cascades and upper Rockies. (Additional reporting by Keith Coffman in Denver; Reporting By Mary Wisniewski; Editing by Greg McCune and Bob Burgdorfer)