Embassy staff are trying to trace up to 350 Australians who remain unaccounted for in Nepal following Saturday’s 7.9 magnitude earthquake, which is so far known to have claimed around 3600 victims.

Mother-of-two Renu Fotedar, 49, from Melbourne, died when her tent was washed away by a wall of snow, according to Temba Tsheri, managing director of Dreamers’ Destination Treks and Expeditions. Mr Tsheri – quoted in the Daily Telegraph – said sherpas who survived the avalanche had told him she stood no chance.

“She was right in base camp. She was inside the tent. A big avalanche came and a lot of people were washed away. There was no time,” he said. “It was so fast it was like a dream – they couldn’t do anything. There was a big sound; they didn’t get the chance to run away. There was no place to hide. I lost one Australian, one Chinese and two sherpa, and all my friends are in hospital.”

Ms Fotedar – an Indian-born Australian from Melbourne – was working in Switzerland as a motivational speaker. She leaves two sons, aged 17 and 15.

Meanwhile Australian actor Hugh Sheridan is heading for Everest in a bid to find his 20-year-old brother Zachary, from Adelaide, who has not been heard from since the earthquake. He had been trekking for days on his way to base camp.

Writing on Twitter, Hugh said: “I will be with a small crew helping with a chopper, doctor, and we will have a satellite phone available for any Australian there who needs to reach home and tell their loved ones they’re okay.” He added: “Stay positive everyone, I feel optimistic that he is alive and stuck.”

Damage to infrastructure has made communications difficult, but Australian prime minister Tony Abbott attempted to reassure those still waiting to hear from loved ones. “Australians do go trekking in that part of the world, and if someone is trekking in that part of the world we shouldn’t assume the worst,” he said, quoted in the Sydney Morning Herald.