Climbers are tweeting about being trapped on Mount Everest after earthquake-triggered avalanche kills 18

Photo by Paula Bronstein/Getty Images

Mount Everest is shown at approximately 29,035-foot in Nepal.

Climbers who became trapped on Mount Everest after a massive earthquake in Nepal triggered an avalanche are using social media to send out updates on the scale of devastation on the world's tallest peak.

Rescue operations for stranded climbers are continuing Monday.

The 7.9-magnitude earthquake was Nepal's worst in 80 years. It caused a massive avalanche on Everest that wiped out parts of the mountain's base camp.

At least 18 people were killed by the avalanche and 61 are injured, according to the latest reports.

There were more than 800 people at different places on the mountain when the avalanche struck around noon local time on Saturday, Ang Tshering Sherpa, president of the Nepal mountaineering association, told AFP. 

On Monday, Romanian mountaineer Alex Gavan said on Twitter that rescue helicopters were only able to take two people at a time because of the high altitude. 

Gavan has tweeted several updates from base camp, which he said looked like the aftermath of a "nuclear blast."

Climbers and rescuers have also been dealing with aftershocks from Saturday's quake.

Mountain guide Adrian Ballinger tweeted Sunday:

Six helicopters landed at Mount Everest base camp on Sunday, while ropes and other climbing equipment are being flown to those still trapped above the Khumbu icefall, AFP reports.

"Those who are able are walking down. Others are being airlifted to Pheriche," a spokesman for Nepal's tourism told the news organisation. 

A video shot by German adventurer Jost Kobusch, which surfaced Sunday, shows the moment the earthquake-triggered avalanche slammed into Mount Everest base camp, sending climbers fleeing into tents and behind rocks. 

The incident will no doubt renew the debate over the safety of local guides, or Sherpas, who are hired to lead wealthy foreign climbers up the world's tallest peak. Overcrowding, which can lead to bottlenecks, has made the mountain increasingly dangerous. 

Last year, 16 Nepalese Sherpas were killed by an avalanche as they were working to prepare the route with equipment and ropes ahead of the main climbing season. Before Saturday's earthquake, this was considered the deadliest day in Mount Everest's history. The 2014 climbing season was cancelled as a result. 

The earthquake has killed at least 3,600 people and left more than 6,500 people injured nationwide, Nepalese authorities said Monday.