Four Canadian hikers are among more than a dozen people who have died following an avalanche and a blizzard in Nepal's Himalayas, with many more believed to be missing.

The exact number of dead was not immediately clear, but several media reports indicate at least 20 people are dead after bad weather hit the Annapurna Circuit, a popular hiking area. Search efforts have been hampered by bad weather but were expected to resume early Thursday as crews scour the rugged area for the missing.

The Trekking Agencies Association of Nepal said Wednesday that five bodies have been recovered from the Phu area in Manang.

"Four of the deceased are Canadian and one is from India," the statement says.

Prime Minister Stephen Harper said on Twitter that he and his wife "express our condolences to the families and friends of the four Canadians who lost their lives in an avalanche in Nepal," he wrote.

The identity of the deceased and where they are from has not yet been released. Canada's Foreign Affairs department did not confirm the Canadian deaths Wednesday, but said in a statement they were aware of the reports that Canadians were affected and were in contact with local authorities.

"Our thoughts are with those affected by the avalanche in Nepal," a spokesman said in a statement. "To protect the privacy of affected individuals, we cannot release further details at this time."

Search on for missing trekkers

Still more people are missing and stranded around the Annapurna region, the trekking association says, but the rescue efforts could be complicated by weather and the remote location.

Rescue helicopters have been deployed to the area to help with the effort, but information about how the process will unfold was scarce early Thursday in Nepal.

A Facebook group dedicated to connecting trekkers in Nepal since the avalanche posted a picture from Oct. 9 of Jane Van Criekingen, left, and Virginia Schwartz, right. (Facebook)

Earlier in the day, CBC News was told six Quebecers were missing. Later in the day, sources clarified that three people among a group of six Quebecers were among those missing and feared dead.

"A search is still ongoing to find the three missing persons and Terra Ultima remains in constant communication with the local authorities," a statement from the Montreal-based travel company said.

Two Ottawa women are believed to be among the missing and a Toronto-area man says he is concerned his brother and the brother's girlfriend are also among the missing.

Mark Schwartz confirmed Wednesday that his sister, Virginia Schwartz of Ottawa, and her friend, Jane Van Criekingen, are missing and unaccounted for.

A Facebook group dedicated to connecting trekkers in Nepal since the avalanche posted a picture of the two women from Oct. 9. It is not yet known if these two women were part of the Terra Ultima group that left Quebec.

The avalanche occurred near the Phu region of Nepal. (Hannah Wise/CBC)

Nadia Chychrun, meanwhile, said she hasn’t heard from her brother and his girlfriend since Oct. 12. The pair were in the area trekking.

Marc Voyer, 38, and Rose Maninang, 39, were halfway through the Annapurna circuit and were on their way back down, Chychrun said.

"It's all very sketchy at the moment," Chychrun told CBC News. "Foreign Affairs doesn't seem to have much information yet either."

The death toll could rise as rescuers continue to try to locate and move the missing. The rescue effort has been tricky, because search crews have to work in remote areas in bad weather

October is the most popular trekking season in Nepal, with thousands of foreigners hiking around Nepal's Himalayan mountains. The Thorong La pass is also on the route that circles Mount Annapurna, the world's 10th highest peak.

The rough weather is linked to cyclone that hit neighbouring India. According the Nepal News, the district areas of Manang, Myagdi and Mustang were particularly hard hit by the weather.

Locals and trekkers killed

Three villagers were killed Monday in the same district, about 160 kilometres northwest of the capital, Kathmandu, and their bodies were recovered on Wednesday

In the neighbouring Mustang district, four trekkers caught in a blizzard died Tuesday.

Rescuers recovered the bodies of the two Poles, one Israeli and one Nepali trekker from the Thorong La pass area.

It was initially thought that the group had been caught in an avalanche, but government official Yam Bahadur Chokyal said the four trekkers had been caught in the blizzard and died.

He said another 14 foreign trekkers have been rescued so far, and two army helicopters were picking up injured trekkers and flying them to Jomsom town.

Five others — two from Slovakia and three Nepalese guides — were hit by a separate avalanche on Mount Dhaulagiri and remained missing.

An avalanche in April just above the base camp on Mount Everest killed 16 Nepalese guides, the deadliest single disaster on the mountain.

Climate experts say rising global temperatures have contributed to avalanches on the Himalayan mountains.