TORONTO - A Toronto-based quantum computing researcher admired by his friends for both his intellectual and physical prowess has gone missing during a mountaineering trek to India, relatives and colleagues said Wednesday.

Peter Wittek was taking part in a nearly month-long effort to summit Mount Trisul, a roughly 5,700-metre peak in the Himalayas. Five of his six climbing companions managed to escape when an avalanche hit on Sunday, but Wittek has not been seen since.

Gergo Oberfrank, Wittek's younger brother, said he's on tenterhooks as Indian authorities mount a search-and-rescue effort amid uncertain weather conditions. But Oberfrank said his brother has a better chance than most of defying the odds and being found alive.

“That guy is made of iron,” Oberfrank said in a telephone interview from Wittek's home country of Hungary. “He's emotionally, mentally and physically the strongest person I have ever met. If there is a person who can survive this, it is him.”

Wittek has earned an international reputation in the field of quantum machine learning and wrote the first book on the subject, according to colleagues.

After completing his PhD in Singapore, he moved to Canada in early 2018 to take up a position with the University of Toronto.

The university's Rotman School of Management issued a brief statement saying Wittek was on faculty as an assistant professor, adding staff were in touch with his relatives and offering support to his colleagues and students.

Social media posts offering prayers and support for his safe return came from major global academic institutions including the science publication Plos One and the Perimeter Institute in Waterloo, Ont.

U of T said Wittek's trip to India was not connected to his work with the school, a fact corroborated by his friend and training partner.

Mark Fingerhuth met Wittek at an international quantum computing conference and eventually followed him to Toronto to take part in a university-run program he was spearheading.

He said Wittek had been an avid mountaineer for at least a decade, summitting peaks that included Mount Kilimanjaro in Tanzania and Mount Aconcagua in Argentina.

He had been preparing for the Trisul expedition for nearly a year, Fingerhuth said, undertaking a strict regimen that included running up the stairwells of Toronto condo buildings while wearing at least 20 pounds of weights.

Wittek also regularly practised his climbing skills and attended a mountaineering course weeks before his departure that was meant to equip him for a wide variety of emergency scenarios.

“This course was focused on how you would rescue yourself,” Fingerhuth said. “The problem is, with an avalanche, you can't really prepare for that.”

Wittek's friends and relatives said the avalanche that hit his climbing party struck while the climbers were at a site well above base camp.

Oberfrank said Indian authorities have mounted a search and planned to fly over the peak with helicopters on Wednesday or Thursday, weather permitting.

He said both Indian and Canadian government officials have been responsive and supportive during a particularly trying time.

Global Affairs Canada did not immediately respond to request for comment from The Canadian Press.

Oberfrank said that while his confidence is tested further with each passing day, he has no choice but to remain optimistic that his brother will be found.

“Hope is the last thing I have,” he said. “I have to be focused and capable even though I am desperate. And it is extremely hard.”

This report by The Canadian Press was first published on Oct. 2, 2019