CALGARY, Alberta (Reuters) - Three renowned professional alpinists are missing and presumed dead after an avalanche in Canada’s Rocky Mountains, Parks Canada said on Thursday.

Climbing media named the men as American Jess Roskelley, 36, and Austrians David Lama, 28, and Hansjörg Auer, 35, saying they were killed after attempting to climb a challenging route on Howse Peak in Banff National Park.

Canadian authorities did not release the names of the three men, but said they were one American and two Europeans and described them as highly experienced professional mountain athletes.

Roskelley was best-known for climbing Mount Everest at age 20 in 2003, making him the youngest person at the time to have climbed the world’s highest mountain.

Lama and Auer were also world-class mountaineers who had climbed some of the toughest routes around the globe.

Parks Canada said in a statement the party was attempting the east face of Howse Peak. The three men probably started their ascent on Tuesday, Stephen Holeczi, Parks Canada visitor safety specialist said.

They were reported overdue on Wednesday.

“Parks Canada visitor safety specialists immediately responded by air and observed signs of multiple avalanches and debris containing climbing equipment,” the statement said.

Without providing details, Holeczi said there was “strong evidence” that all three climbers were deceased.

There currently is no timeline for when search and recovery efforts can begin, Holeczi said, because of bad weather and avalanche risk in the area.