A 16-year-old boy has died following an accident at Lynn Canyon Park, RCMP say.

Authorities said the teen from Pennsylvania was swimming near Twin Falls, east of the suspension bridge, on Friday afternoon when he was sucked over a second waterfall and fell as far as nine metres into another pool.

Bystanders managed to pull him from the water, and one who was trained as a lifeguard started CPR, police say. Emergency crews had to perform an 18-metre rope rescue to get him out of the park. The boy was in life-threatening condition when he was taken to Lions Gate Hospital, where he later succumbed to his injuries.

"This is an extremely tragic situation. Not just for the North Shore but for the family of the youth involved," Cst. Brett Cunningham told CTV News.

The boy was visiting family in Vancouver and they were on the North Shore for the day enjoying the sun in Lynn Canyon, Cunningham said.

Emergency crews are called to Lynn Canyon every year to save people from either the trails or Lynn Creek. Youths often cliff jump into the rushing waters, despite posted warnings and the pleas of emergency crews to avoid dangerous activity.

Last year, a 17-year-old boy from Port Coquitlam drowned after bypassing a fence and cliff jumping near the suspension bridge.

People at Lynn Canyon Friday, however, said they think the water is fine.

"I think when you're in the water it's pretty safe. Just maybe stay away from the edge of the water falls," Eric, who didn't want to use his last name, said.

"If you stay smart and stay with the calm water, then by all means I'd say it's safe," said Josh Donko, another man at Lynn Canyon said.

It is not illegal to swim or jump in Lynn Canyon, but Cunningham said police are working to try and prevent incidents like this.

"We want to remind the public of the dangers of these waters and abide by the cautionary signs and fences that are posted," Cunningham said.

With a report from CTV Vancouver's Allison Tanner.