Seventeen bodies have been recovered on Mount Everest base camp after a severe earthquake on Saturday set off an avalanche, making it the deadliest disaster in the history of mountaineering on the world's highest peak.

Sixty-one people were injured when part of the base camp was engulfed by the snowslide, Ang Tshering Sherpa, president of the Nepal Mountaineering Association, told Reuters.

A first helicopter took off from Kathmandu on Sunday morning to airlift the injured after flights were delayed by cloudy weather, Sherpa said.

There are around 100 climbers at camps 1 and 2 on Mount Everest, above base camp, and all are safe, Sherpa said. It will be difficult to evacuate the climbers as the route back to base camp through the Khumbu icefalls is blocked, he said.

The avalanche that swept through parts of base camp had the combined force of two separate snowslides from different peaks, Sherpa said, and blanketed the camp in powder snow.

Google engineer killed

One of those killed was Dan Fredinburg, a Google engineer based in California. He died as a result of head injuries when the avalanche hit, according to a statement from the mountaineering company that had taken him to base camp.

"We pray too for all those who have lost their lives in one of the greatest tragedies ever to hit this Himalayan nation," Jagged Globe said.

Dan Fredinburg was on Mount Everest with three other Google employees (Instagram) Lawrence You, Google's director of privacy, posted online that Fredinburg was with three other employees climbing Mount Everest. The other three, he added, are safe. Fredinburg served as product manager and the head of privacy at the company's experimental division Google X.

Tourism ministry officials estimated that at least 1,000 climbers, including about 400 foreigners, had been at base camp or on Everest when the earthquake struck.

April is one of the most popular times to scale the 8,850-metre peak before rain and clouds cloak it at the end of May. Almost exactly a year ago, an avalanche killed 16 Nepali guides in what was the single deadliest day on the mountain.

Saturday's 7.8-magnitude quake was the strongest to hit Nepal for 81 years. It also shook neighbouring India, China and Bangladesh. Early on Sunday, the official death toll stood at more than 1,900 people in Nepal and the surrounding area.

Romanian climber Alex Gavan made a desperate appeal for a helicopter to fly in and evacuate climbers: "Many dead. Much more badly injured. More to die if not heli asap."

Huge disaster.Helped searched and rescued victims through huge debris area.Many dead.Much more badly injured.More to die if not heli asap. —@AlexGAVAN

He later tweeted that there are casualties and many people are injured at Everest base camp. Many people have responded to that tweet asking if Gavan knows whether their loved ones are safe.

Carsten Lillelund Pedersen, a Danish climber, said about 40 people were being treated in a makeshift hospital at a tent at base camp. He said many of those injured had back injuries from being hit by rocks and ice when running from the avalanche.

The poor visibility after the first avalanche meant it was "difficult to see the following avalanches, and there are so many - maybe one every 5 min. - that I have stopped counting", Pedersen said on Facebook.

Quebec climber Gabriel Filippi, present at Everest base camp, said on his Facebook page that Quebecers there with him were unharmed.

"Powerful earthquake at the base camp of Everest," he wrote in French. "Several deaths, wounded and missing. All Quebecers are safe and sound."

'Please pray for everyone'

Raymond Sartor from Newmarket, Ont., said his son, 19-year-old Dylan Sartor, may have been at Everest base camp when the avalanche happened. His son stopped in Nepal to trek up to base camp on his way home from a university exchange program in Sweden.

Dylan Sartor texted his dad this photo on Friday, saying he would be trekking to Everest base camp over the weekend. He posted to his Facebook page on Sunday saying he was just below the camp when the avalanche hit but he's OK. (Submitted by Raymond Sartor) "It seems to me he might be in the heart of all this," Raymond told CBC News.

He said Dylan sent a text earlier this week, with a selfie showing Everest in the background, saying that he would be there for the weekend. On Friday, he sent a message to one of his friends, saying he was at 1,250 metres.

For the length of his trip, any text messages family and friends attempted to send to Dylan bounced back. But today, his phone has been accepting texts, his dad said.

"But, he's not responding, so I don't know what hope that is," Raymond said.

He, his daughter and son are meeting in London, England, and flying to Kathmandu on Tuesday.

"The whole family is going to go find him," he said.

Elite Calgary climber Raphael Slawinski sent a text message saying "all good on the North Side," presumably not from the base camp that was hit by the avalanche. Slawinski had not responded to further inquiries from his communications manager Jo Salamon, but he is presumed to be safe.

Another climber, Daniel Mazur, said the base camp and the icefall route had been "severely damaged," and his team was trapped.

"Please pray for everyone," he tweeted.

Aftershock! <a href="https://twitter.com/hashtag/Everest?src=hash">#Everest</a> team is in camp 1, hanging on. <a href="https://twitter.com/hashtag/Icefall?src=hash">#Icefall</a> route destroyed. —@danielmazur

﻿ Struggling to assess number of dead, injured

Mohan Krishna Sapkota, joint secretary in the Nepalese tourism ministry, said the government was struggling to assess the damage on Everest because of poor phone coverage.

"The trekkers are scattered all around the base camp and some had even trekked further up," Sapkota said. "It is almost impossible to get in touch with anyone."

Choti Sherpa, who works at the Everest Summiteers Association, said she had been unable to call her family and colleagues on the mountain. "Everyone is trying to contact each other, but we can't," she said. "We are all very worried."

An avalanche triggered by the earthquake in Nepal swept across Everest Base Camp, seen here on Saturday night. (Azim Afif via AP) Last year's tragedy prompted the Sherpa guides to complain that their safety was being neglected, but there were no immediate recriminations on Saturday.

"This will definitely have some impact on climbing activity, but this is a natural disaster. No one can do anything," said Ang Tshering Sherpa.