BOISE, Idaho – Heavy snow pummeled Western states from Washington to Arizona, closing schools and government offices, causing widespread havoc on roads and even shutting down one ski resort.

A search was under way Tuesday for three snowmobilers missing in the Colorado mountains.

The roofs of several businesses collapsed under the weight of snow Monday in northern Idaho, while avalanches forced the evacuations of dozens of homes. There were no injuries.

The Navajo Nation declared an emergency on its sprawling reservation.

About 20 inches of snow fell Monday around Coeur d’Alene. “They got clobbered,” John Livingston, a National Weather Service meteorologist, said of residents of that northern Idaho city.

The storm system arrived from hard-hit California and combined with another emerging from the Gulf of Alaska, stalling over eastern Washington and northern Idaho, said Livingston.

Forecasters predicted a new storm could roll in on Tuesday, bringing 1 to 3 more inches of snow in low-lying areas of Idaho and 2 to 4 inches in the mountains. The weather service posted heavy snow warnings for parts of Washington, Oregon and Idaho.

The San Juan Mountains of southern Colorado were socked with 30 inches of snow Monday and wind gusts as high as 100 mph. At Durango, about 340 miles southwest of Denver, even sledding hills were at risk of avalanches after 18 inches of snow fell.

A search got under way Tuesday morning for three snowmobilers missing since Sunday in the mountains of Colorado’s Summit County, west of Denver, said sheriff’s spokeswoman Paulette Horr. She said relatives didn’t notify authorities until Monday evening, and searchers couldn’t start sooner because of bad weather and avalanche danger.

Three friends who went looking for the missing snowmobilers also were stranded but got out Monday after spending the night at a cabin, authorities said.

Two snowmobilers were rescued Monday in eastern Oregon’s Wallowa Mountains, where 4 feet of snow fell, after being missing over the weekend.

The snow closed Coeur d’Alene schools on Monday, the first time since November 1996 that a winter storm closed the city’s schools, officials said.

City Hall was closed Monday at Spokane, Wash., which got a record 13.7 inches of snow. Officials urged residents to stay home Monday to give snowplows a chance to catch up.

Avalanches in Idaho damaged four houses and a garage northwest of Ketchum and police evacuated 71 homes in the area as a precaution for much of Monday, said police spokeswoman Kim Rogers.

The storm caused hundreds of wrecks all over Utah and Idaho, and multiple road closures, including Interstate 84 at the Idaho-Utah line.

Skiers were stuck at Utah’s Snowbird resort because Little Cottonwood Canyon was closed to traffic for avalanche control, spokeswoman Laura Schaffer.

The threat of flooding as heavy snow melted brought an emergency declaration on the Navajo reservation – sprawling across parts of Arizona, Utah and New Mexico.

“Protecting life, limb and property is always our first priority,” said Navajo President Joe Shirley Jr. “Real dangers exists in our remote areas miles from paved roads.”

At lower elevations of Arizona, heavy rain flooded some creeks and rivers. Some residents of the town of Carrizo fled for a time because of fear that two dams might fail. The evacuations were canceled after water levels lowered and an inspection found no apparent damage to the dams.

California finally saw clearing weather Monday after a week of downpours and heavy snowfall, but the reprieve might not last long. There was a 20 percent chance of rain Wednesday, and two more storms, weaker than the storms that hit during the past weekend, were forecast to reach the region on Friday.

Associated Press writer Arthur H. Rotstein in Tucson, Ariz., contributed to this report.