TORONTO - Treacherous water, howling winds and an angry buffalo all contributed to deaths or suspected deaths across Canada this long weekend.

Tragedy struck central Ontario cottage country Sunday when three swimmers disappeared near Lake Muskoka.

Seven people, all believed to be in their 20s, went into the rain swollen Moon Falls River, but only four came out. The three who didn't are presumed drowned.

An Ontario Provincial Police dive unit looked for the missing swimmers on Sunday and again on Monday but had to call off the search due to the dangerously fast current. The dive team plan to resume the search Tuesday morning.

The Muskoka area was the scene of a second tragedy Monday, when a small float plane crashed in the woods near Torrance, about two hours north of Toronto.

There were two people aboard the Cessna 206, and both were killed.

Vicious winds were blamed for two deaths in Alberta over the long weekend.

Donna Moore, 35, was struck and killed by a huge speaker Saturday night when gale force winds collapsed part of the stage at the Big Valley Jamboree country music festival in Camrose, Alta. At least 75 other concert goers were injured, two of them critically.

In downtown Calgary, a three-year-old girl was struck and killed by a piece of sheet metal that powerful winds sent flying from a hotel construction site. Her father and seven-year-old brother were also taken to hospital with non-life-threatening injuries.

In Pincher Creek, Alta., a 71 year old man died after being attacked by a bison as he walked along a rural road. The huge animal inflicted severe injuries to the senior's head and abdomen.

Canada's highways and byways also contributed to the holiday weekend death toll.

A grandfather and granddaughter died Friday after their vehicle left a rural road in eastern Ontario and hit a tree. A post-mortem showed that the grandfather had died of a medical condition just before the crash.

In Saint John, N.B., a 60-year-old woman was killed in a head-on collision.

A 22-year-old Mississauga, Ont. man died in a collision an hour southeast of Ottawa, and four people died in two crashes in the Edmonton area.

But not all of the weekend carnage was accidental.

Wesler Fabian, 25, of Ottawa, was shot early Saturday and left to die outside a hotel in Toronto's upscale Yorkville shopping district.

It was the city's 32nd homicide of 2009.