Footage has emerged of the moment an avalanche swept into Everest Base Camp after a powerful earthquake hit Nepal.

German climber Jost Kobusch was filming the lower slopes of the world's highest mountain when a mass of snow rushed in with a force described as being like a "nuclear blast".

The mountaineer is seen running for cover in his tent before being enveloped in a blanket of icy material.

You can watch the video below. Viewers are advised it contains strong language:

Mr Kobusch is heard saying "hold on to my jacket" as the wind threatens to blow his colleague away.

Both are believed to have escaped serious injury but 18 other climbers are known to have died.

They are among more than 3,600 people now known to have killed in Nepal by Saturday's 7.8-magnitude quake.

Britons Sam and Alex Chappatte and Captain Tim Bradshaw were also hit by the avalanche but survived.

Sarah Chappatte, a family member who has been in contact with Sam and Alex, said on the couple's blog: "We need to get them out.

"We believe there are around 100 climbers and sherpas trapped between camps one and two. Some of the climbers are beginning to suffer from altitude sickness.

"All reports confirm that the icefall is now impassable so there is no way to climb down."

Sherpas with facial injuries were seen in footage arriving at hospital in Kathmandu after being flown back from Everest's slopes.

One of them, Gyelu Sherpa, said: "The snow swept away many tents and people."

Another, Bhim Bahadur Khatri, added: "We all rushed out to the open and the next moment a huge wall of snow just piled on me.

"I managed to dig out of what could easily have been my grave. I was suffocating, I could not breathe. But I knew I had to survive."

Concern is growing for dozens of climbers trapped high up on the mountain.

Several aftershocks caused further avalanches as a rescue attempt was in progress to airlift those injured at base camp to safety.

One of those who died in the first avalanche was 33-year-old Google executive Dan Fredinburg.

The death toll from the avalanche made it the mountain's deadliest disaster to date.

Tourism ministry officials estimating that at least 1,000 people, including some 400 foreigners, were at base camp or on the ascent to the peak as the earthquake struck.

It is not clear whether the largest aftershock - one at 6.7 magnitude - resulted in further casualties.