The team made the discovery while descending from the Central Rongbuk Glacier on the north face of Everest in September.
Along the way, they found an oxygen cylinder with the date 1933. An expedition to Everest that year found an item that belonged to Irwin.
Encouraged by this possible sign that Irwin’s body could be nearby, the team searched the glacier for several days before one of them saw a bot emerging from the melting ice.
It was a fortuitous find – they calculated that the ice had only been melting for a week before their discovery.
The foothill has since been removed from the mountain due to concerns that ravens were reportedly disturbing it, and handed over to Chinese mountaineering authorities, who manage Everest’s North Face.
For Irwin’s descendants, the discovery was emotional – especially in this, the centenary year of his disappearance.
Summers grew up hearing stories about her grandmother’s adventurous Oxford-educated younger brother, whom they knew as “Uncle Sandy”.
“My grandmother had a picture of him by her bed until the day she died,” she recalled. “She said he was a better person than anyone ever was.”