A Nepali climbing guide thought to have died on Mount Everest has been found crawling down to Base Camp, six days after he was last seen alive.

Dawa Sherpa was last seen above Camp 3, at around 7,500m (24,600ft), while coming down the mountain after summiting.

Hopes for his survival were slim as the air at that altitude is thin – but on Thursday, a cleaning crew spotted the experienced climber, who had frostbite on his hands but appeared to be in good health, sliding slowly down.

“Dawa managed to survive against all odds for days. It’s nothing short of a miracle,” said Pemba Sherpa, executive director of 8K Expeditions which was overseeing search efforts. “This is a true self-rescue.”

Five people have died so far in this year’s climbing, three of them Nepalis who were involved in the Everest preparations, according to news agency AFP.

More than 1,000 reached the Everest summit this season, making it the busiest on record.

Dawa Sherpa – also known as Hillary Dawa Sherpa after famed mountaineer Edmund Hillary – was “slowly sliding through” the Khumbu Icefall toward Base Camp when he was found, Pemba Sherpa said.

“As far as I know, no one has survived alone at that altitude on Everest so far. This is a miracle to have survived for six days alone and descended safe. I think he must have lived inside the tents to keep himself safe,” said Pemba Sherpa.

Dawa Sherpa is “awake and undergoing treatment”, according to Nishant Dhakal, a doctor in the intensive care unit of Kathmandu’s HAMS Hospital.

“He recognised me … is good and speaks,” his daughter Mhendo Lhamo Sherpa told Reuters news agency after visiting him. “We are happy.”

Before he was found, the 52-year-old’s wife told AFP that she had offered last rite prayers for his soul.

On Wednesday, Chris Thrall, a climber and former British Royal Marine, posted a tribute on Instagram for Dawa Sherpa, thinking he had died on the mountain.In the video, Thrall recalled that Dawa Sherpa had “sat down for a rest with his backpack” as they descended from Camp 4, the highest campsite before the summit.

“And I turned and I said, ‘Hillary, are you okay, brother?’ He said, ‘Yes, yes, fine Chris, please go, go!'” Thrall said. “This is nothing new, you know, I’d go ahead, he’d go ahead.”

As Thrall went down he found a struggling Polish climber who was part of their group, and they continued descending together. But Dawa Sherpa never caught up with them.

“It had been a long summit push. What should have been five days to the summit and back took us 11 days, that’s how challenging the conditions were,” Thrall said.

“So, do I go back for Sherpa, who’s probably going to rock up and be fine, as he has done hundreds of times before?” he added.

One relative, Kung Sherpa, had expressed dissatisfaction over the pace of the search in an interview with Outside, an adventure sport publication.

The search, when it did commence, was launched by a company called 8K Expeditions, which eventually was able to airlift him to safety.