Calgary emergency crews searched the Bow River Monday for two missing rafters who are feared dead after their rafts went over a weir known as "the drowning machine."

The missing men were among a group of nine friends who were floating down the river Sunday when they ran into trouble.

A search boat scouring the Bow River for signs of the missing rafters.
(CBC)

Three rafts holding five people went over the weir. Of those five, emergency crews were able to pull three to safety, but two others vanished.

None of the rafters was wearing a life-jacket.

Claudie Tremblay, one of five friends on the trip who had recently moved to Calgary from Quebec, said the group had been on the river about two hours when they suddenly came upon the small dam.

When asked by CBC News what he was thinking, he said: "I don't know … I am going to die."

One of the other rafters, Carl Langlais, said he'd been down the river before but this time he couldn't get to shore.

"We can't exit the river because the river is so high," he told CBC News.

Safety boom broken

Langlais said he was surprised to see that the boom — a gate that normally crosses the Bow River before the weir — was broken.

Jeff Budai of the Calgary fire department said a safety boom is usually in place to prevent anyone on the river from entering the dangerous area, but the boom was washed away last week during localized flooding. The river is still too high to put the boom back in place.

"They do call this the drowning machine," Budai said of the weir. "We urge our citizens to stay away from the water. We are having record-high water flow right now. With that safety boom being washed away, you have no way out."

The weir — or low head dam — was built slightly downstream of the Calgary Zoo in 1904 to divert water from the Bow River into an irrigation canal.
(CBC)

The last time the other rafters saw their two missing friends, they were waving their arms for help and couldn't break free from the powerful churning of the weir.

Calgary fire Capt. Dave Clark says he can't believe anyone survived.

"Nobody really gets out of there alive at all and these people were lucky they did get out — lucky with how the water affected them and how they got pushed out," he said.

Budai said rescuers' greatest fear is that the rafters were pinned under the weir. While there's a chance they found their way to the river bank, if they've been in the river all night "things are looking pretty grim," he said.

The fire department's aquatic team was dispatched to take a closer look Sunday but couldn't find anything.

The search was called off at sunset and was to resume Monday.

Site of a $6.4-million makeover

The weir — or low head dam — was built slightly downstream of the Calgary Zoo in 1904 to divert water from the Bow River into an irrigation canal.

The Parks Foundation Calgary wants to turn the dangerous waters around the Bow River weir into a safe place for canoeists and kayakers.
(Parks Foundation Calgary)

It creates an impassable, recirculating wave for canoeists and kayakers. A dozen people have died at the weir over the past 30 years.

The Parks Foundation Calgary wants to raise the water level over the weir so it's no longer a problem. Kayakers and canoeists would then be able to travel safely along that section of the river, where rocks will be placed to create navigable rapids and calm pools.

Work on the $6.4-million project will start later this year and should be complete in a year or two, depending on river conditions. The cost is being covered by the province, the city and the Calgary Foundation.

With files from the Canadian Press