Undated (AP) _ A storm moving out of the Rockies and onto the Plains blasted Wyoming and Colorado with heavy, wet snow Tuesday, closing schools and hundreds of miles of highway and shutting down the Wyoming Legislature.

Wyoming's Laramie Range near Granite Mountain had picked up 3 to 4 feet of snow and some mountain areas in Colorado got up to 2 feet overnight. Earlier, the storm left 22 inches at Snowbird, Utah.

Ahead of the advancing snow, freezing rain brought down power lines in western Nebraska. New Mexico and western South Dakota got snow and Kansas had strong thunderstorms.

Jack Daseler, a meteorologist at the National Weather Service in Cheyenne, Wyo., described the conditions responsible for the storm as ''a classic,'' combining an upper level weather system near the Four Corners area, where Colorado, Utah, Arizona and New Mexico meet, and a surface system in southeastern Colorado.

He said that during the night ''the upper and lower system will coincide over east-central Colorado and sit there for 12 hours.''

He predicted total accumulations of 15 to 18 inches in Wyoming's lower elevations. Cheyenne had more than a foot by noon and Wheatland had 18 inches.

Pinewood Springs, Colo., in the foothills seven miles southwest of Loveland reported 24 inches of fresh snow and Buckhorn Mountain west of Fort Collins received 22 inches. In New Mexico, 9 inches of snow had fallen by late morning at Chama and Brazos Lodge.

Heavy snow hampered rescue efforts after a bank explosion at Crested Butte, Colo., and delayed the arrival of ambulances from Gunnison, officials said.

Wyoming legislators decided to take a day off from their budget session as the snow deepened outside and blowing snow made buildings just a block away in Cheyenne start to fade out. About 4,000 state employees were told to stay home and at least 400 miles of interstate highways were closed.

''Getting people home tonight is the concern,''said Senate Majority Leader Diemer True. ''We could get staff and legislators here, but getting them home tonight is the problem.''

Neither House Speaker Bill McIlvain, with 18 years in the Legislature, nor Senate President Russell Zimmer, a 16-year member, could remember the Legislature ever closing because of the weather.

Children in Cheyenne and Laramie got the day off, and the University of Wyoming in Laramie canceled classes at 11 a.m.

''They're calling for another foot,'' university spokesman Bill Young said.

The University of Wyoming's Cowboys were stranded in Laramie by road closures that kept them from making their flight from Denver to the Western Athletic Conference basketball tournament in El Paso, Texas.

Rodney Barkell, manager at a 7-Eleven store in Cheyenne, said he had almost no business. ''What we mostly get right now is walk-ins - people that are close enough to where they can walk'' to the store.

And some of those who did take their cars may have regretted it. ''We've had a bunch of people stuck in our parking lot,'' he said.

Barkell added that he was 1 1/2 hours late for work himself and he only lives a mile away. ''I got stuck trying to get out of my house, and a friend of mine tried to pull me out and he got stuck, too,'' Barkell explained.

The Wyoming Highway Patrol closed some 200 miles of Interstate 80 from the Nebraska line west to Walcott Junction, and about 150 miles of Interstate 25 from the Colorado line north to Orin Junction.

The closures piled up business at truck stops in Cheyenne.

''We're jammed,'' said Richard Fox, general manager of Little America in Cheyenne. ''Everything is full. The truck parking lot is jammed with trucks and all of our motel rooms are rented. We probably have a couple of hundred people waiting around the coffee shop and lobby.''

In northern Colorado, Interstate 25 was closed by heavy snow from north of Wellington to the Wyoming line. The Colorado State Patrol also closed Highway 287 from Fort Collins to Laramie, Wyo.

Denver's Stapleton International Airport reported delays in arrivals and departures because of visibility problems. Spokesman Richard Boulware said visibility was reduced to 1,000 feet at one point in the morning.

Colorado's Poudre Valley Rural Electric Association spokesman Larry Graff said a major transmission line and five substations were down, affecting 3,000 customers north of Fort Collins. Fort Collins Light and Power also reported some outages in the city, including radio station KIIX, which was temporarily off the air.