A major artery between Colorado and the Western United States was buried by a massive avalanche Tuesday that stranded thousands of motorists and scrambled emergency cleanup crews.

In Montana and Washington, avalanches have already killed four people in the past week, the Colorado Avalanche Information Center said.

Three backcountry guides died in avalanches in Washington and another guide was buried in Montana's Glacier National Park last Thursday.

No fatalities were reported in Colorado's avalanche Tuesday, that caused a 15-foot high snow barricade and covered parts of Interstate 70 (I-70).

I-70 goes due west from Denver through the Rocky Mountains and into Utah, the primary corridor from Colorado into Nevada, California, and the Pacific Northwest,and was also hit hard buy a recent rash of winter storms.

The avalanche occurred just after 3 a.m. local time (0900 GMT) at the top of Vail Pass at an elevation of 10,662 feet.

"We got lucky and no one was hurt," Colorado Department of Transportation (CDOT) spokesperson Tracy Trulove told Xinhua.

Three tractor-trailer trucks were reported knocked over by the blast of snow that stretched 50-yards wide, Truelove said.

It was eight hours before CDOT crews had cleared one lane of traffic, and Trulove said her teams were also mobilizing in the southwest part of the state where more heavy snows were expected for the next few days.

In just the past week, six feet of snow has fallen in the southern Colorado ski resort town of Crested Butte and another 30 inches of snow is expected by Thursday morning.

"With all the recent rains and moisture falling on top of snowpack, it created optimal avalanche conditions," CDOT Director of Communications Amy Ford told Xinhua.

An avalanche warning was in effect until Wednesday for a dozen mountainous areas across Colorado, including ski resort towns Steamboat Springs, Aspen, and Vail.

Crested Butte was closed Monday, but ski resorts across the state welcomed the snow, hoping it will bring more customers.

CDOT took advantage of Tuesday's I-70 shut-down to stage a "controlled mission" atop I-70's other major peak closer to Denver, whereby an avalanche was intentionally triggered by explosives with motorists miles stopped away.

Crews worked until 4 p.m. local time (2200 GMT) next to the mile-long Eisenhower Tunnel at 11,158-feet to clear a 150-yard wide, mitigation controlled avalanche, a strategy CDOT performs with the Colorado Avalanche Center.

CDOT had both avalanches cleared by Tuesday afternoon.

Ford said CDOT was preparing other "controlled missions" on mountain passes across the state to prevent motorists from being trapped or killed from unplanned avalanches.

In Colorado on Tuesday, Loveland Pass, Berthoud Pass, and Monarch Mountain were closed due to avalanche danger.

CDOT officials told Xinhua they were preparing explosives for more mitigation efforts in the next few days.

source: Xinhua