Witnesses described a chaotic scene in which workers tried to get out of harm's way as the crane was coming down.

"It was the scariest thing I've ever seen," said Miriam Halpenny. "I was talking to another woman who said she saw a man falling from the top."

Hours after the incident, Kelowna RCMP confirmed that more than one person was killed, but said they were "releasing limited information" on the extent of the tragedy, in part because authorities were still working to notify next of kin.

"Not all persons have been properly identified, and so right now, all we can tell you is that there have been multiple fatalities from people in that area," Insp. Adam MacIntosh said.

Part of the crane fell from the construction site, striking a neighbouring office building and a senior's home. Part of the crane was left standing.

The following addresses were evacuated due to concerns about ongoing danger in the surrounding area: 47 - 612 Bernard Ave., 1450 - 1488 Bertram St. and 1441 - 1471 St. Paul St.

In a news release, the Central Okanagan Emergency Operations Centre said the accident scene remained "unstable" as of Monday afternoon. Structural engineers were dispatched to assess the damage and determine what needs to be done to ensure the area is safe.

"Road and sidewalk closures, including barricades, are in place to ensure safety. Residents and visitors are to stay out of the area," the release said.

The crane collapse happened at the Brooklyn construction site run by developer Mission Group. The company described the incident as a "catastrophic failure (in which) a crane fell during the dismantling process."

"Mission Group immediately evacuated the building and emergency crews were dispatched to the site. We continue to work closely with emergency responders to assess the situation," the developer said in a statement.

"Mission Group expresses its deepest sympathy for the families of those affected by this tragedy. We have set up support services to help those in need."

Kelowna RCMP said one person remains unaccounted for, and that officers are working to determine the individual's whereabouts and well-being.

WorkSafeBC has also sent teams to investigate what happened. In a news release, the agency said it would be working to determine "the cause of the incident, including any contributing factors, so that similar incidents can be prevented from happening in the future."