Vernon RCMP spokesman Gord Molendyk said at least one person is killed or injured in the Rattlesnake Point area every year. ((CBC))

A Vancouver medical expert is warning people about the dangers of cliff jumping after a 21-year-old man was killed on Saturday afternoon in Kalamalka Lake Provincial Park in B.C.'s Okanagan Valley.

Vernon RCMP spokesman Gord Molendyk said the Salmon Arm man jumped from the 15-metres high cliff at Rattlesnake Point and never resurfaced.

"One witness said that it appears as though he didn't come feet first. He came sideways when he hit the water, and they never saw him resurface," said Molendyk. It appeared alcohol was involved, he said.

The area is extremely dangerous and at least one person is killed or injured there every year, cautioned Molendyk.

"There were signs up above that diving area, or the area where they jump off, explaining the dangers, that individuals have been hurt but they continue to dive off those cliffs," he said.

Police are not releasing the young man's name until his family has been notified.

Dr. Richard Simons, the trauma director at Vancouver General Hospital, said it's important people know jumping off anything higher than six metres can be deadly.

"You're travelling at freeway speed and at that speed, when you hit water, it's like hitting concrete … Catastrophic injuries can occur, particularly head and spine, and then internal injuries causing bleeding," said Simons.