Two young men in their 20s died in separate accidents on B.C. waters on Monday.

Police were searching Okanagan Lake on Tuesday for the body of a 25-year-old Kelowna man who fell off a pontoon boat the night before.

The victim was out on the boat with friends after an evening of wakeboarding and fishing when the operator suddenly slowed the engine. The victim was not wearing a life jacket and fell over the side.

His friends heard a bump as the boat passed over him and then briefly saw him floating. But when they jumped in, they couldn't find him, despite spending an hour searching.

Fire and rescue boats searched the area Monday night, and police boats continued the search on Tuesday.

Kelowna RCMP Const. Steve Holmes told ctvbc.ca that the group had been drinking, but only lightly. "It didn't appear that any of them were affected by it."

Police have no yet released the victim's name.

Cascade Falls drowning

A 22-year-old Surrey man was also killed Monday afternoon when he became trapped underneath the water at a popular park east of Vancouver.

The victim was with friends when he fell into the water at Cascade Falls Regional Park near Mission, B.C., around 4:30 p.m. Monday.

Mission RCMP say the man was walking on the rocks and fell into the water.

"Police were advised that male did not come up out of the water despite attempts from a friend nearby," Cpl. Sharon Siluch said in a statement.

Crews from Mission Search and Rescue recovered the man from the fast-moving water a short time later but attempts to resuscitate him were unsuccessful.

RCMP told CTV News the incident is being considered an accident. The man's name is not being released.

The main attraction of the park -- located northeast of Mission -- is its eponymous waterfall, which drops 30 metres into a large pool. The park also features several natural pools used by swimmers.

Deadly week on B.C. waters

On Sunday, the body of a 76-year-old man was retrieved from Lake of the Woods in Hope, B.C.

Police believe he likely drowned or suffered from another type of medical distress while in the water.

A 17-year-old international student from China drowned in Alice Lake near Squamish.

The Lifesaving Society of B.C. says there is an average of 80 to 90 drownings in B.C. every year.

Drowning is the second most common cause of death in Canada, next to traffic accidents. In July and August, one person drowns every two days on average in B.C. alone.