SEATTLE (AP) — Heavy snowfall and high winds on Tuesday kept searchers away from a remote, jagged peak in Washington’s Cascade Mountains, where an avalanche killed three climbers from the northeastern U.S. over the weekend.

The slide struck Sunday as a group of six climbers were ascending a steep, snow-packed gulley on the 8,705-foot (2,653 meters) Colchuck Peak, about 70 miles (113 kilometers) east of Seattle in the Alpine Lakes Wilderness, Chelan County sheriff’s Sgt. Jason Reinfeld said Tuesday.

Four of the climbers were swept about 500 feet (152 meters) down the slope. One of the four survived, a 56-year-old man from New York, and despite some injuries he was able to confirm that the other three were killed before working his way back to their base camp at Colchuck Lake, Reinfeld said.

The two members of the climbing party who were not swept away did not immediately descend to base camp, but remained about two-thirds of the way up the gulley — called a couloir — and saw three additional avalanches come down, burying two of the deceased climbers.

A seventh member of the group, one who remained at base camp rather than participate in Sunday’s climb, hiked out to get help — an arduous overnight journey that included a descent of about 4,000 vertical feet (1,219 meters) over 8 miles (12.9 kilometers). He was able to contact the sheriff’s office by 8 a.m. Monday to relay what had happened, Reinfeld said.

A mountain rescue team reached the base camp early that afternoon but decided against venturing above the lake due to the avalanche risk.

The searchers returned with the surviving climbers on Monday and declined to even attempt to reach the area on Tuesday amid a heavy snowstorm and wind gusts of up to 60 mph (96.6 kmh).

Members of the Northwest Avalanche Center and mountain rescue crews planned to head back on Wednesday to assess the hazards at the scene, Reinfeld said.

Those killed were identified as a 53-year-old man from Connecticut, a 60-year-old woman from New York and a 66-year-old man from New Jersey. Reinfeld said the group had some mountaineering experience, but he did not know the extent of it.

The avalanche was the the deadliest in the U.S. since four backcountry skiers were killed in an avalanche in Utah two years ago.

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