Mingma Rita Sherpa was not home when the muddy torrent roared into his village in Nepal without warning, but when he returned, he did not recognise his once beautiful settlement.

It took just moments for freezing floodwaters to engulf Thame in the foothills of Mount Everest, a disaster that climate change scientists say is an ominous sign of things to come in the Himalayan nation.

"There is no trace of our house ... nothing is left," Sherpa said. "It took everything we owned."