Rampant drinking and out-of-control crowds, compounded by "significant challenges and planning misses" for the city and police, led to the Stanley Cup riot, according to an independent report.

The report from John Furlong, the former head of Vancouver's Olympic committee, and Douglas Keefe, a former Nova Scotia deputy attorney general, also applauds a "heroic effort" by police to bring the chaos under control.

"Why did the riot occur?...The riot occurred because villains and thugs acted up," Keefe told reporters at a press conference Thursday.

"The question that is a more valuable question is: how did they get the edge?"

The answer, according to the authors, is "congestion and free-flowing alcohol" -- an immense, and unanticipated crowd of drunk and rowdy hockey fans.

"Vancouver tried to do a good thing and found itself in an almost impossible situation. There were too many people, not too few police. No plausible number of police could have prevented trouble igniting in the kind of congestion we saw on Vancouver streets that night," the authors wrote.

An estimated 155,000 people crowded into the downtown core to watch Game 7 of the Stanley Cup Final between the Vancouver Canucks and the Boston Bruins on June 15, according to the report, titled "The Night the City Became a Stadium." The entire report is available here.

"Essentially the city core became a stadium holding 155,000 people but without resilient infrastructure, time, or capacity to manage the crowd," the report says.

As it became clear that the Canucks had no chance of winning, the crowd grew increasingly raucous, hurling bottles at the giant TV screens until the game ended and then moving on to burning cars and looting stores.

"Alcohol fuelled nasty behaviour and triggered law breaking that surprised and galled us all," the authors said.

They estimate that alcohol sales on June 15 were 68 per cent higher than on the same day in 2010 -- some stores even doubled their sales.

The temporary fan zones set up downtown were appropriate for about 34,000 people -- the number they were designed to contain -- but were far too small and had too few security checkpoints for the number who showed up for the game.

Too many people arrived in the downtown live zone too early in the day for police to respond appropriately. Many of those pushing their way into the fan area were already drunk, while others drank openly after they arrived.

"VPD's crowd management strategy is good, but is predicated on setting and maintaining a tone of responsible celebration. The opportunity to set a tone passed before there were enough officers to set it and congestion prevented its later imposition," the authors say.

For the first time, the report revealed the amount of police officers responding to the mayhem. A total of 928 police officers from a number of jurisdictions eventually responded to the downtown area, although the deployment began at less than half that number with 446.

In comparison, just 359 officers were deployed to manage the crowds after the 2010 Olympic gold medal hockey game.

The report says that police responded appropriately as the riot began, gathering riot gear and ramping up the number of officers available.

However, "the transition was slow due to communications problems and location of the riot equipment in the packed streets," the authors say, and better planning is required for future events.

It took as long as 40 minutes for officers to transition to tactical gear, and the location where it was stashed "was not a good location," according to Keefe.

Police also faced equipment troubles. The batteries in the VPD's long-range acoustic device -- a sort of sonic gun used to disperse crowds -- had not been charged, so the device had to be plugged into a police car at all times.

An RCMP loud speaker in the southern area of the downtown core also malfunctioned, and the crowds were not warned that tear gas was about to be deployed.

"Given that the size of the crowd made communication at an individual level between police and citizen impossible, the use of LRADs and loud hailers is that much more important. Communication was not used with this crowd until the situation was out of hand," the report says.

Cell broadcasting, social media could be used in emergency response

The report offers 53 recommendations for the city and the Vancouver Police Department, but also concludes that recommendations made after a similar hockey riot in 1994 were largely respected and implemented.

One new suggestion is something called "cell broadcasting," a system that allows authorities to send official text messages to all cell phone within a specific area, including visitors from other cities.

"Everybody was walking around with one of these," Furlong told reporters Thursday, holding up a cell phone. "Everyone has one, and some people were using these and not for good reason."

An emergency cell broadcasting system for B.C. would be the first in Canada, although the technology is already in use in India and South Korea.

The authors also suggest that the city and police should promote their Twitter accounts before large public events so that officials can tweet warnings and advice.

Vancouver should not shy away from large public gatherings, the authors say. "The streets should not be surrendered to thugs and villains. People should be able to congregate downtown in harmony without the need for police on every corner."

The authors also suggest that a special court should be established to process the people accused of participating in the riot, and even that those convicted in connection with the riot undergo restorative justice, forcing them to confront the business owners and emergency workers impacted by the chaos.

"A guilty plea and imposition of a fine teaches nothing of the harm that's been done," the report says.

"First responders, business people, people who took part in the clean up, perhaps some of the victims, could teach them real lessons a judge can only lecture them about. Maybe a hockey player could tell them how they shamed the club after a magnificent season."

The report also recommends special measures to cut back on people drinking openly on transit and in the streets; Furlong said the SkyTrains acted like a funnel to push drunken revellers into the downtown area.

Police chief, mayor respond

Chief Jim Chu says he is impressed by the efforts of Furlong and Keefe to review the riot.

"The question we have all asked, including myself, is there anything we could have done differently to ensure that there would not have been a riot? And secondly, is there anything we could have done differently to stop it immediately before it could get started?" Chu said in a statement.

"Sadly it would seem that there is no magic solution to protect ourselves from those intent on creating this type of harm."

He also defended the VPD's decision not to reveal the number of officers deployed during the riot, and questioned why it was included in the report.

"I have always told you that we don't discuss the numbers for security reasons. Why would anyone want to give riot instigators more aid to commit their crimes?" he said.

Chu says he will now be reviewing the recommendations in the report.

The department has conducted its own review of the riot, and will be showing it to the police board on Tuesday.

Mayor Gregor Robertson said the report from Furlong and Keefe provides a "pragmatic and thoughtful framework" for future large public events.

"The recommendations from Mr. Furlong and Mr. Keefe are tangible, we can move quickly on them, and I am committed as mayor to seeing all the recommendations for the city put into action," he told reporters.

He said the city will be working with province on solutions for controlling alcohol consumption during public events.

The City of Vancouver released its own internal review into the riot late Thursday afternoon. That report also points to alcohol and huge crowds as factors leading to the chaos. The report estimates that the total cost of the downtown live sites -- including policing, sanitation and the giant TV screens -- was about $1.5 million.

The city's report makes a number of recommendations, including the formation of new committees to plan public events and better communication between the city, the province, TransLink, police and Canucks management.