A snow-covered tent has been the only possible sign of two climbers missing on the world's ninth-highest mountain since Sunday. A flash of reddish-orange fabric amid a sea of white was spotted Thursday during a helicopter search of Pakistan's 26,660-foot Nanga Parbat, which also turned up evidence of heavy snowfall or possibly an avalanche, reports Rock and Ice. Brit Tom Ballard, 30, and Italian Daniele Nardi, 42, are last known to have reached 20,670 feet, or more than 3,000 feet above the tent's position. The experienced mountaineers set out in January hoping to be the first to scale Mummery Rib, the steep western face of the peak dubbed Killer Mountain. They persisted through poor weather and heavy snow, even as two Pakistani team members abandoned their efforts, per Outside.
Two cooks and a Pakistani military officer remaining at base camp heard from Ballard and Nardi on Sunday, as the climbers were between Camps 3 and 4. But radio silence followed bad weather, which obscured the mountain from view. As conditions cleared Wednesday, the climbers appeared to have vanished. Helicopters and rescuers were allowed to arrive Thursday, though airspace had been closed amid a dispute between Pakistan and India. No trace of the climbers was found, per the New York Times. This was Nardi's fifth visit to Nanga Parbat. Ballard—whose mother died on K2 in 1995, a few months after she became the first woman to scale Mount Everest without an oxygen supply—is the first person to solo climb all six major north faces of the Alps in a single season. (A climber died on Nanga Parbat last year.)