A deadly avalanche that swept over heli-skiers in British Columbia’s Purcell Mountains on Monday, killing three, was a reminder that even with experience and the right gear “something can surprise you,” a rescue manager said.

RCMP said in a news release that the slide came down on the east side of Kootenay Lake in southeast B.C., burying the skiers.

A transport helicopter was nearing the group at a staging area when the pilot saw the avalanche coming and sounded the alarm, police said on Tuesday.