WELLINGTON, New Zealand — A New Zealand man and his son are feared dead following an avalanche on the world's second-highest mountain, K2.

Marty Schmidt, 53, and his son Denali, 25, were last heard from Friday.

Marty Schmidt had been posting about the pair's climb on the website for Macpac, which sells outdoor equipment. Last week he wrote they hoped to become the first father-and-son team to reach the summit of K2, on the Pakistan-China border.

But Macpac on Monday posted a message saying Base Camp reports indicated the pair had been killed in an avalanche.

British climber Adrian Hayes wrote on his Facebook page that Schmidt last radioed on Friday and that Hayes' fears for the pair were confirmed when Nepalese Sherpas discovered their camp had been wiped out, probably as they slept.

Hayes said the pair were well-known, experienced and strong mountaineers. But he said that other climbers had turned back Friday due to unsafe snow conditions.

"Sadly, at times the mountains do not differentiate between ability and experience, least of all K2," Hayes wrote. "The poignancy of the tragedy is not lost in that, had the rest of us not turned back that day — including Marty and Denali's Australian teammate Chris Warner — we also all would have been sleeping at Camp 3 when the avalanche struck."