Image copyright Handout Image caption From left: Jess Roskelley, Hansjörg Auer and David Lama on what is believed to be the summit of Howse Peak last Tuesday a day before they were reported missing

Three professional mountaineers have been found dead after an avalanche at Canada's Banff National Park.

Austrian climbers David Lama, 28, and Hansjörg Auer, 35, and US citizen Jess Roskelley, 36, had been attempting to climb the east face of Howse Peake.

The group were reported missing last Wednesday and later presumed dead, but recovery efforts were hampered by weather conditions.

The men were part of a team sponsored by outdoor clothing line North Face.

Canadian authorities said air rescuers had seen "signs of multiple avalanches" where they were found.

In a statement, Parks Canada said it "[extended its] sincere condolences to [the men's] families, friends and loved ones".

"We would also like to acknowledge the impact that this has had on the tight-knit, local and international climbing communities," it added.

During their expedition, the group had been taking a route up Howse Peake, known as M16, which has only been climbed once before.

Image copyright Parks Canada Image caption Howse Peak, Banff National Park

Family members of the climbers told Parks Canada they believe the trio did summit the mountain, and that they descended Howse Peak along a similar route.

Rescue efforts were delayed by the weather, and the three climbers were not wearing avalanche beacons when they were found.

"In this case the outcome wouldn't have changed, but it would have expedited the search and recovery," said Parks Canada incident manager Shelley Humphries.

It took 28 staff members about five days to recover the bodies, which were located using a specially-trained avalanche dog attached to a long line from a helicopter.

Image copyright Parks Canada Image caption The bodies were located with the help of a specially-trained avalanche dog

Brian Webster, safety manager for Parks Canada, said the three men were undoubtedly skilled enough to make the climb, but that an avalanche of that magnitude would be difficult to recover from.

Parks Canada believes it was a level-3 avalanche, which is strong enough to knock over trees, bury vehicles or demolish small wooden buildings.

All three were renowned within the mountaineering community.

Mr Lama was part of a duo that carried out the first free ascent of Cerro Torre's Compressor route in Southern Patagonia.

Recently, Mr Auer had also completed a solo ascent of Lupghar Sar West, a 23,559ft (7,181m) peak in Pakistan's Karakorum range.

Image copyright Handout Image caption Jess Roskelley with his wife Alli in January 2019

In 2003, Mr Roskelly became the youngest American to climb Mount Everest - the world's highest peak - aged 20 at the time.

His father, John, was also a mountaineer and climbed Howse Peak via a different route in the 1970s.

"It's just one of those routes where you have to have the right conditions or it turns into a nightmare," he said in an interview last week with The Spokesman-Review newspaper.

"This is one of those trips where it turned into a nightmare."