The bridge across Buffalo Pound Lake, north of Moose Jaw on Highway 2, collapsed Saturday morning while a crane was working on the structure. (Sheryl Rennie/CBC)

A bridge in southwest Saskatchewan is in ruins after collapsing Saturday morning while a crane was working on it. No one was injured as the crane operator jumped to safety.

The bridge, part of Highway 2, is on the causeway that crosses Buffalo Pound Lake, a reservoir north of Moose Jaw.

"One of the cement pads that the crane was on gave way," David Williams, who witnessed the collapse, told CBC News. "The whole crane toppled over, right into Buffalo Pound Lake on the west side of the causeway."

Williams estimated the time of the collapse was 6:20 a.m. local time. He was on the causeway, waiting his turn to drive across the bridge.

"The guy that was in the crane jumped out," Williams said, adding that everyone working on the bridge ran to safety before the crane fell.

"[The crane] started on fire, too," Williams said, although he noted it was mostly smoke and did not last long.

The provincial Highways Ministry says work on the 45-metre bridge began Aug. 9 and was estimated to cost $2.2 million.

Williams said it appeared that one of the support pads that had yet to be worked on was the one that gave way.

Technical experts from the ministry were on the scene to investigate.

"We're relieved that no one was hurt," Saskatchewan Highways Minister Jim Reiter told CBC News. "But we're certainly concerned that it happened at all."

He said he hopes to know more about what happened early next week.

Reiter said the first job is to get the crane out of the water. He said plans are also being formulated on restoring traffic flow and fully repairing the bridge.

Reiter said it might be possible for light traffic, such as passenger vehicles, to use a portion of the bridge that was not affected by the collapse.

"The hope, actually, is that some time next week it will be open to one-lane traffic," he said Saturday.

Roadblocks are in place directing motorists to take alternative routes.

"It's been an unusual year for highways this year," Reiter noted, alluding to roads that have been damaged by flooding. "We've had our challenges this year."

According to information from Discover Moose Jaw, the bridge is 46 years old.