It reported a fourth friend witnessed the incident and ran down the mountain to call for help.
Corporal Sascha Banks of Canada's federal police service said the victims were in their 20s and 30s and were swimming in a pool system at the top of the falls "and then walking along the ledge shortly thereafter". They fell nearly 30 metres.
A family member of Mr Gamble confirmed his death to The Associated Press.
The Shannon Falls is the third-tallest waterfall in British Columbia and police were forced to call in search and rescue teams and helicopter units in order to recover the bodies, as the "extremely difficult" and "very dangerous" terrain combined with a heavy water flow made for a risky recovery effort.
Mr Gamble's girlfriend Alissa Hansen posted an emotional tribute to Instagram.
A GoFundMe page has been set up to support Ms Hansen.
High On Life had almost 500,000 subscribers and the team's last video, about the best things to do in Bali, was uploaded just four days ago.
In 2016, the group was forced to apologise after walking into restricted areas in Yellowstone National Park around the Grand Prismatic Spring.
In the apology on Facebook, they said they had made a $5000 donation to the park and they had made a mistake that "doesn't reflect our respect for the environment".
— with AP
