(From left) Climbers Prasanta Gorai, Debraj Dutta and Subrata De on Tuesday. (Bishwarup Dutta)

For a mountaineering quartet from the city, 90 minutes on Plateau peak came after 17 days of crossing mountain streams in spate, climbing vertical rock walls, walking through knee-deep snow and a week of weather-induced confinement in a 7ftx8ft tent.

Bad weather was the toughest challenge the team from the Calcutta wing of the Himalayan Club faced on their way to the 7,287m summit in the Eastern Karakoram range.

On July 20, seven days into the expedition, they had to descend from the final camp at 6,366m to Camp I at 5,391m because of non-stop snowfall.

“There was a rainbow-like halo around the sun... bad weather was round the corner. There was continuous snowfall for the next seven days and we were confined to a tent in Camp I,” said team leader Debraj Dutta, who returned to the city along with deputy leader Subrata De and Prasanta Gorai on Tuesday.

The fourth member, Pradeep Chandra Sahoo, had reached the city earlier.

“The climb required a lot of mental strength. The final ascent took 14 hours,” said De, a Santoshpur resident who runs a company that cleans glass windows and facades.

Holding fort from 4,706m was base camp manager Biplab Banerjee, “the engine of the expedition”. Sahoo’s wife Chetna, the lone woman in the team, climbed to Camp II at 6,015m. “I decided to return since I was running a temperature,” she said.

Identifying a route and fixing ropes tested the climbers’ skills because Plateau was virgin territory — unconquered.

“After identifying the route we had to fix ropes on the difficult sections and climb down very carefully,” said Sahoo.

But the rope between Camp II and Camp I, a distance of 300m, had disappeared. The group had to descend with the help of crampons and ice axes which Gorai — at 26 the youngest among the quartet — described as “third leg of a mountaineer”.

Mark Richey, former president of the American Alpine Club, wrote on Tuesday: “Congratulations on your success on the first ascent of Plateau peak, a longstanding challenge of the eastern Karakorum.”