Six climbers have been killed in a 1,010-metre fall on the steep north slope of Mount Rainier in the US state of Washington.
It is the worst disaster on the mountain in more than three decades.
Searchers found tents and clothes, mixed with rock and ice, among debris along the Carbon Glacier at 2,900 metres. the National Park Service said. The group's climbing route, to Liberty Peak, is prone to slides and considered relatively difficult.
The six climbers - two guides and four clients from Seattle-based Alpine Ascents International - were last heard from at 6pm on Wednesday by satellite phone. At that time the party was at 3,900 metres with plans to camp overnight. When they failed to return on Friday as planned, the company contacted park rangers. Alpine Ascents is the company that lost five Sherpas at Mount Everest this spring.
At Mount Rainier, the search on Saturday by helicopters and climbing rangers was suspended four hours before dark.
"They feel there is no chance of survival at this point," said Fawn Bauer, a spokeswoman for the National Park Service.
This is the worst climbing disaster on Mount Rainier since June 21, 1981, when 11 climbers were killed by an avalanche on Ingraham Glacier, on the southeast side of the mountain.
Exactly how the climbers fell is unclear. They could have been climbing on a snow slope that gave way, or may have been swept off by rock and ice debris, according to park rangers. Avalanches also occurred in the general area.
The climb's leader was Matt Hegeman, of California, Alpine Ascents confirmed. Hegeman's company biography says he has climbed Rainier more than 50 times, using four different routes. The identities of the other five were not released.
Mount Rainier is one of the world's most popular climbs, attracting between 10,000 and 11,000 climbers a year. Alpine Ascents brought 955 guides and clients up the mountain in 2012.
The six climbers set out on Monday and they reached 3,260 metres on Tuesday. A few inches of snow fell on Wednesday night and Thursday. It would not have been unusual for Thursday to pass without phone contact as the climbers made the final push to the 4,300-metre high Liberty Summit, according to park spokeswoman Patti Wold.
The Liberty Ridge route is considered difficult and fickle. It includes at least two glacier crossings and a steep final ascent, where ice and rock can fall on climbers.
Climbs in June pose dangers of collapsing ice ledges as the winter snowpack rapidly melts. But it is really the only chance to climb Liberty Ridge, before further melting exposes cracked and crumbly rocks.
It may be weeks or months before the bodies could be recovered, if at all, said Wold. "If they are in a spot that's dangerous, we can't risk other climbers."
There were 89 deaths while summiting Rainier between 1897 and mid-2011, and another 25 deaths from 1912 to mid-2011 on other types of climbs or training.