Rioters had overturned a car and set it on fire outside Vancouver's main library, but police held off plunging in among hundreds of people on the scene because they were hard-pressed to distinguish rioters from bystanders, the city's police chief says.
As the damage was being cleaned up on Thursday, Jim Chu said police needed time to figure out how to defuse the situation, which escalated into chaos across the downtown core.
"Sometimes you have to stop and pause before you can regain more ground," Mr. Chu told a news conference after what is being called the worst disturbance in Vancouver since the Stanley Cup riot of 1994.
He said if officers had run to every hotspot without an overall plan, the riot would have lasted longer than the three hours it took for police to gain control - half the time it took to subdue the 1994 violence, in which the chief, then a sergeant, suffered bruises.
Vancouver police, including members of the public safety unit, or riot squad, went into the evening mingling in small groups with the crowds, a long-standing tactic that the chief called "meet-and-greet," but scrapped that approach when trouble began.
Police then assembled into larger groups to deal with the disorder, working block by block and focusing on the safety of people caught up in the chaos.
"The riot broke out. The plan shifted from meet-and-greet to regroup and deploy," Chief Chu said.
By the time police acted, the riot was under way. Another 14 vehicles were burned, nine police officers were injured and police ended up arresting 101 people Mr. Chu characterized as "criminals, anarchists and thugs" for breach of the peace, public intoxication and such crimes as theft, mischief, assault with a weapon and break and enter.
Two people were charged in a stabbing. Vancouver firefighters responded to 387 incidents, including fires and medical calls.
Chief Chu said the city was vulnerable to people who came downtown with canisters, gas masks and even fire extinguishers to use as weapons, including some implicated in smaller riots during the 2010 Winter Olympics.
Vancouver police were not alone on Wednesday. They had on-scene backup from other regional forces, including the RCMP and police in New Westminster, West Vancouver and Port Moody as part of long-standing co-operation agreements.
Once the rioting began, officers from Abbotsford headed into the city to assist. Chief Chu said off-duty officers from his own force also came to help.
Thousands of people were massed into public viewing areas around the city library. Asked whether such gatherings should be capped in future, Chief Chu said that was something worth looking at. However, he noted that large crowds were out for Games 5 and 6 of the Stanley Cup final, and those gatherings ended peacefully.
About 400 officers were on hand for the evening, which saw an estimated 100,000 people gather in the streets for the Stanley Cup final. By comparison, there were 6,000 police at the G20 in Toronto on June 26 last year, the main day of protests by some 30,000 people, some of whom went on a violent rampage through the downtown core.
Chief Chu said police did their best, and even more draconian plans would not have guaranteed a riot would not happen. "There's many places in the world with more police officers and authoritative states and riots still occur," he said.
Police are welcoming the submission of video and pictures from members of the public to help with the investigation into the riot, which has become a regional effort uniting forces across the Lower Mainland.
Media reports suggested up to 500 police officers were on duty in the city core during the riot, but the Vancouver police would only say hundreds of officers were present.
Bob Whitelaw, a risk-management consultant who co-wrote the B.C. Police Commission report on the 1994 riot, said he could not comment on whether enough police officers were on the ground this time.
"There is no one ratio. It depends on the event, the crowd, the amount of alcohol involved," he said. "What one would have to look at in an inquiry is what the police plan was, what was the distribution of regular officers versus riot police."
Steve Summerville, president of Ontario-based Stay Safe Instructional Program and a former Toronto police staff sergeant, said the Vancouver department did a good job with the numbers it had. However, he questioned why more officers weren't on the ground.
"It would certainly appear that the resources that were deployed - subject to a post-mortem - would be that they were not in a position to handle the violence or civil disobedience that did indeed take place."
Chief Chu acknowledged calls for his resignation but he shrugged off the post-riot criticism and said he will not quit his post. "There are many Monday-morning quarterbacks," he said.
With reports from Justine Hunter in Victoria and Sunny Dhillon in Vancouver