CALGARY - A mountain climber from Calgary has died on Mount Everest after making it to the summit without the use of oxygen.
At least two climbing websites have confirmed the death May 21 of Frank Ziebarth, 29, who moved to the city two years ago from Germany.
Ziebarth is reported to have reached the summit on the Tibetan side, and was last seen at 8,700 metres determined to descend under his own strength.
''Very sadly, Frank could not make it back to high camp, suffering from hypothermia and obvious lack of oxygen,'' his climbing partners, Alexandre Pare, Manuel Pizarro and Anna Baranska said in a statement posted on EverestNews.com.
''It was later confirmed by fellow climbers that his body now rests peacefully at the bottom of the third step, high on Mount Everest.''
His colleagues said Ziebarth was an accomplished high-altitude climber who already made it to the top of at least three other peaks without the use of oxygen.
Pizarro declined an interview request. He said he will speak about what happened once he returns to Canada next week.
Ziebarth was engaged to Christina Ziegler of Calgary.
There are unconfirmed reports that Ziebarth was the fifth person to die on the world's tallest peak this climbing season. About 300 people reached the top of the 8,849-metre high mountain this year - many of them in the last few weeks.
Veteran mountaineer Sharon Wood didn't know Ziebarth, but said climbing the iconic mountain is becoming so commonplace that some attempt more difficult routes with fewer resources - including trying to reach the summit without oxygen.
The idea is to make the climb as pure an experience as possible.
''Climbing Everest without oxygen is related to style,'' she said. ''You are going for the maximum amount of efficiency. If you don't have a lot to back you up you have to be very proficient - that's good style.''
Wood, the first North American woman to summit Everest, said some mountaineers want to separate themselves from less experienced climbers by making an already dangerous task even more challenging.
But more challenge means more risk.