Calgary Police are again asking for the public’s help to locate a man who went missing after going out onto the Bow River, the third who has disappeared in a short period of time.

On Wednesday afternoon, police say that 37-year-old Derek Blackrider got into the water at Shouldice Park for a swim.

Witnesses soon lost sight of him.

The CFD Aquatics Team, Calgary Police, and HAWCS searched for Blackrider but found no trace of him.

He is described as:

  • Aboriginal
  • 5’8”
  • 150 lbs
  • Brown hair
  • Wearing glasses

Authorities say he was wearing a red shirt and dark jeans at the time of his disappearance.

Blackrider is the third man to have gone missing after going out onto rivers in Alberta, and the second on the Bow in recent months.

On June 7, Stephen Samson's family reported him missing and police believe he is the same person that witnesses spotted having trouble in the water on the Bow River near the end of May.

He was trying to get back into a capsized dinghy when he slipped back under the water and disappeared.

Police found the boat and an oar but nothing else.

Rescue teams, along with friends and family of a missing man, have also been scouring the Highwood River.

Justin McNeil, 19, was with friends at the Nature's Hideaway Campground on Sunday when he slipped into the fast moving water.

There has been no trace of him despite their efforts.

The Calgary Fire Department is reiterating its advice for residents that if they want to go out onto the river, they should scout the water first for potential hazards, assess the danger, and always wear a lifejacket.