Quebec heart specialist Dominique Ouimet, 48, was among several people still missing Monday in northern Nepal on Mount Manaslu, the world's eighth-tallest peak.
Officials say at least nine people are dead after the avalanche roared through their camp around 4 a.m. Sunday, while more than two dozen climbers were still sleeping in their tents.
Rescue teams scoured the area Monday for six missing climbers.
The doctor's sister, Isabelle Ouimet, told Radio-Canada in an interview she had not given up on the possibility that her brother is still alive.
"Even if the chances are, perhaps, slim, I think we have to hang on to the idea that he is made strong, that he is without a doubt in a good position in hope that he receives our energy," she said.
"For now, I think this is what we have to do."
A passionate and experienced mountaineer, Ouimet undertook the Himalayan expedition to raise money for his patients in the cardiology unit of a hospital in St-Jerome, north of Montreal.
He spoke just last week about why he started this fundraising endeavour.
"I asked myself, 'Why don't I connect my personal passion with something useful, something more altruistic and that goes beyond just me?' " Ouimet told Radio-Canada from a Himalayan camp at an altitude of 4,820 metres.
He was also asked whether he had thought about the dangers of climbing such a mountain. Ouimet replied there are many security precautions to follow on such a climb and he listed a few.
"We think more about these little details than any eventual catastrophe," said Ouimet.
"Of course, when we do this and we remain concentrated, it goes well."
On Monday, four rescue helicopters scanned the slope's peak in search of the missing, while climbers and guides conducted searches by foot.
Ten climbers survived, but many of them were injured and were airlifted to hospitals.
By midday, rescuers had brought down eight bodies and were trying to retrieve the ninth from the 7,000-metre area where the avalanche struck, police Chief Basanta Bahadur Kuwar said.
At least six more climbers were believed to be still missing. Kuwar said the identities of the climbers killed and missing were still unclear but he confirmed the missing included Ouimet.
His sister posted a comment later Monday on the Facebook page for Expes, a company that organizes climbing expeditions, to say rescuers had stopped their search.
"For now, the searches have been suspended," Isabelle Ouimet wrote.
"Dominique is still missing. The chances of finding him alive, according to mountain guides in Nepal, are virtually zero."
On Sunday, she had expressed disappointment and frustration about the lack of information she was getting about the situation in Nepal.
"I'd like it if someone in the organization would take the trouble to provide us with news," she wrote on her own Facebook page.
"Nobody has contacted the family of Dominique Ouimet. I've done phone interviews on the radio and television in Canada. I have more tomorrow. I'll have to be honest and tell them the truth: we don't know who's in charge of the search, how the search is being done, what steps have been taken so far. After the shock, anger is rising. Time is of the essence."
In Ottawa, a spokeswoman for Foreign Affairs said Monday the department contacted the family of a missing Canadian to offer consular assistance.
Amanda Reid said Canadian officials in Kathmandu and New Delhi were also working with local authorities to gather more information.
"Our thoughts are with the victims (and their families) of a Canadian citizen who is missing in Nepal and everyone affected by this avalanche," Reid wrote in an email.
Another Canadian, skier and mountaineer Greg Hill of Revelstoke, B.C., was also on Manaslu when the avalanche crashed down. He escaped unharmed.
Hill's cousin, Magee Tabah, said he hasn't talked to Greg, but did speak to his wife. He said she is fine and is hoping he will return home soon. He said Greg's children, although young, know what happened to their father.
Tabah said he first learned his cousin was involved in the incident when he woke up Sunday and went online.
"My first thoughts were, I guess, of worry for him and fear, for I guess I didn't really know what the situation was."
Tabah described his cousin as ''extremely determined. He's incredibly smart.
"He's got an incredibly strong character. He's a very caring, loving man who is an incredible, almost super-human athlete as far as skiing goes.
Dolraj Dhakal, a Nepalese government administrator in the area, said no one saw the avalanche coming and officials were unable describe its size.
Veteran Italian mountaineer Silvio Mondinelli, who has climbed the world's 14 highest mountains, said he and fellow climber Christian Gobbi were sleeping in a tent when they heard a violent sound and felt their tent start to slide.
"It was only a few seconds and we did not know what happened, but we had slid more than 200 metres," Mondinelli told The Associated Press in Kathmandu.
He said another Italian climber and their Sherpa guide were sleeping in another tent and were buried by the avalanche and died.
Gobbi said they were unable to see at first because it was so dark and they had no light.
"We found someone's boots and put them on," he said.
When the sun rose an hour later, they saw parts of tents scattered across the snow, along with people who had been killed or injured.
They said they were able to assist the injured with the help of Sherpa guides who came from lower camps. Those who could walk made their way down to the base camp while those who were injured were picked up by helicopters.
Foreign governments reported casualties Monday.
The French Foreign Ministry said four French climbers were among the dead and two others were missing. Three French climbers were pulled from the snow and taken by helicopter to a hospital in Kathmandu, the ministry said.
"The situation continues to evolve, due to the atmospheric conditions," the government department said in a statement Monday.
Spain's Foreign Ministry said one Spanish climber was killed.
Ten climbers survived, but many of them were injured and were flown to hospitals by rescue helicopters. Two Germans were transported to hospitals in Kathmandu on Sunday, and two Italians were flown there Monday.
Italian, German and French teams were on the mountain, with a total of 231 climbers and guides, but not all were at the higher camps hit by the avalanche.
Sunday's avalanche came at the start of Nepal's autumn climbing season, when the end of the monsoon rains makes weather in the high Himalayas unpredictable. Spring is a more popular mountaineering season, when hundreds of climbers crowd the high Himalayan peaks.
Mount Manaslu is 8,156 metres high and has attracted more climbers recently because it is considered one of the easier peaks to climb among the world's tallest mountains.
Nepal has eight of the 14 highest peaks in the world. Climbers have complained in recent years that conditions on the mountains have deteriorated and risks of accidents have increased.
Veteran guide Apa, who has climbed Mount Everest a record 21 times, travelled across Nepal earlier this year campaigning about the effects of global warming on the mountains.
He told The Associated Press the mountains now have considerably less ice and snow, making it harder for climbers to use ice axes and crampons on their boots to get a grip on the slopes.
Loose snow also increases the risk of avalanches. The cause of Sunday's avalanche was not immediately determined.
Avalanches are not very frequent on Mount Manaslu, but in 1972 one struck a team of climbers and killed six Koreans and 10 Nepalese guides.
Ang Tshering of the Asian Trekking agency in Kathmandu, who has equipped hundreds of expeditions, said the low level of snow and increased number of climbers on Manaslu has made climbing conditions difficult.
"It used to be a low-risk mountain in the past but now that has all changed," Tshering said, adding that conditions have become more unpredictable.
With files by Keven Drews of The Canadian Press in Vancouver
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