Mount Everest Avalanche ‘Came Out of Nowhere,’ Climber Says

APRIL 18, 2014— -- A climber who witnessed today's deadliest avalanche on Mount Everest, which killed at least 12 people, said the snowslide "came out of nowhere," comparing the fallout to a war zone.

"Without warning, a large chunk of ice broke loose," Australian climber Gavin Turner told ABC News.

"There were a few seconds of panic where I thought this is going to collect us."

MORE: 12 Dead in Deadliest Avalanche Ever on Mount Everest

Turner was on his first climb through the Khumbu Icefall, southwest of the summit in the Himalayas in Nepal, when the avalanche occurred. A cloud of snow and dust enveloped the area, followed by a huge thud, he said.

He was okay, but people located higher -- identified as Nepalese Sherpa guides -- were covered by mounds of ice and snow. Twelve are dead and four are missing, according to Nepal's Ministry of Culture, Tourism and Civil Aviation. The guides were fixing ropes for other climbers when the avalanche hit.

"These expeditions wouldn't happen without them. They're the backbone of all the organizations up here," Turner said. "Without the Sherpas, it just wouldn't happen."

More than 4,000 climbers have scaled the summit since 1953 when it was first conquered by New Zealander Edmund Hillary and Sherpa Tenzing Norgay. Hundreds have died attempting to reach the peak.

The worst recorded disaster on Everest, which is the Earth's highest mountain, had been a snowstorm May 11, 1996, that caused the deaths of eight climbers. Six Nepalese guides died in an avalanche in 1970.

The Associated Press contributed to this report.