Two boaters are missing after a canoe capsized on Upper Kananaskis Lake in southern Alberta on Tuesday.

Cochrane RCMP and Kananaskis Emergency Services responded to a report of two missing boaters around 4 p.m. on Tuesday after a canoe with four people flipped over. Officials say none of them were wearing life jackets

Bystanders, using boats and paddle boards, were able to rescue a 30-year-old man and a 34-year-old woman. But another man and a woman, both in their 30s, remain missing. RCMP spokesperson Cpl. Troy Savinkoff said none of the boaters were Canadian citizens, but he could not confirm where they reside.

Emergency crews remained on the scene late Wednesday afternoon, as part of a multi-agency search effort that police say included a helicopter.

Upper Kananaskis Lake is located in Peter Lougheed Provincial Park, roughly 140 kilometres southwest of Calgary.

The incident occurred just a little more than a week after RCMP responded to a call about another capsized canoe in the area.

On Aug. 16, police were called to Barrier Lake, which is roughly 55 kilometres north of Upper Kananaskis Lake. Emergency responders found a 60-year-old man dead at the scene and took a 56-year-old woman with hypothermia to the hospital. A few days later, they located the body of a second victim, a 30-year-old man.