Deaths on Mount Everest continued to mount Friday in the worst disaster in the mountain's history, as a sudden avalanche of ice and snow killed at least 12 climbers, leaving four still missing as of late Friday night in Nepal. The deaths were all Nepalese ethnic Sherpa guides who perform vital functions for the hundreds of foreign climbers who try to reach the top of the world's highest mountain each year.
"The Sherpa guides were carrying up equipment and other necessities for climbers when the disaster happened," said Mohan Krishna Sapkota of Nepal's Tourism Ministry, which regulates and oversees Mount Everest climbs.
The routine was a normal one. Foreign climbers — many of them inexperienced mountaineers and little more than particularly daring tourists who have shelled out thousands for a Mount Everest adventure — wait at a base camp. As they wait, locally-based Sherpas venture up the mountain to prepare climbing routes and fix ropes for the paying customers below.
That appears to be exactly what the Sherpas were doing when a massive avalanche that appeared to "come out of nowhere," according to one climber, cascaded down over them, causing the deaths of what will likely turn out to be more than 12.
"Without warning, a large chunk of ice broke loose," Gavin Turner, of Australia, a climber who was waiting to attempt his way up Mount Everest, told ABC News. "There were a few seconds of panic where I thought this is going to collect us."
Climbers at base camp below the Khumbu Icefall, on a glacier nearly 18,000 feet above sea level, avoided the worst of the avalanche, but the Sherpa guides a few thousand feet above them, fixing ropes for the foreign climbers' attempt to reach the Mount Everest summit, stood no chance.
"These expeditions wouldn't happen without them. They're the backbone of all the organizations up here," said Turner. "Without the Sherpas, it just wouldn't happen."
Though 12 bodies of the Sherpas who met their deaths on Mount Everest Friday were recovered, rescuers said three more bodies had been spotted, so the number of deaths was expected to go up to at least 15 by Saturday morning.
Prior to Friday's tragic avalanche, the deadliest day in Mount Everest history came on May 11, 1996, when climbers were caught in a severe snowstorm that cause the deaths of eight. That disaster was chronicled in the bestselling book Into This Air by author Jon Krakauer who was part of that Mount Everest expedition.