Emergency crews and heli-skiing staff helped rescue five people who were caught up in a backcountry avalanche north of Whistler, B.C., on Monday.

The slide was triggered by “commercial activity” on Ipsoot Mountain, near the community of Pemberton, according to Const. Antoine Graebling with the Sea to Sky RCMP detachment.

Several customers and an instructor from Whistler Heli Skiing were out on the mountain at the time, Graebling said.

Four people were completely buried by the avalanche – including two who spent at least 10 minutes under the snow – while a fifth was partially buried.

“All are alive and all are in stable condition,” Graebling added.

The RCMP said employees from Whistler Heli Skiing and members of the Whistler Blackcomb Ski Patrol launched the preliminary rescue effort.

B.C. Emergency Health Services told CTV News paramedics were notified of the slide around 1:30 p.m., and set up a staging area with three ambulances at a helipad in Whistler.

“Paramedics provided emergency medical treatment to three patients who were transported to hospital,” said Brian Twaites, B.C. EHS spokesperson, in an emailed statement.

Two other people were assessed and treated by paramedics, but did not require hospitalization, Twaites added.

Contacted for comment, Vail Resorts, which has owned Whistler Blackcomb since 2016, said Whistler Heli Skiing is “grateful to its partners and Whistler Blackcomb Ski Patrol for their quick action.”

Everyone who was out on the heli-skiing trip was accounted for following the slide, the company said.