The 16-year-old, believed to be from Dunbartonshire, was with his father and a group of people when they were swept over a 100ft waterfall on the Kettle River, near Grand Forks in British Colombia.

The search is continuing for the 50-year-old who is feared to have drowned after being swept over waterfalls on Saturday afternoon.

The 16-year-old boy frantically swam to shore and raced along the bank in a bid to catch them.

His father is still missing, but the others, Ron and Jacqueline Legare, died after the current sucked them into the dangerous gorge

It is understood the youngster ran all the way down the bank in his rescue bid.

A member of Grand Forks Search and Rescue said the teenager was distraught.

The Legares, of Christina Lake, were with a group of 13 friends and family for a float-tube outing on the Kettle River, which draws hundreds of people daily in the summertime. Royal Canadian Mounted Police said: "The family of the 50-year-old Scottish man have been advised by the RCMP and Grand Forks Victim Services personnel that the man is presumed to have drowned. "

Starting their journey near the community of Gilpin, the group travelled about eight kilometres along mild waters, until they rounded a curve and found themselves swept into the canyon.

The strong current and high waters pulled them past the normal exit point and toward the gorge.

Witnesses at the nearby Cascade Cove campground heard a woman screaming around 5 pm. Rescue officials recovered Ron Legare, 74, shortly after the accident but couldn't revive him. The body of his 71-year-old wife was recovered on Sunday.

It is thought the 50-year-old Scot was visiting the area with his wife and son.

Authorities had warned British Columbia's rivers are especially dangerous this year because of higher than average rainfall and snowmelt causing them to run faster and higher.