Updated at 3:49 p.m.

An independent consultant investigating the February bridge failure at the Martin Olav Sabo Bridge in Minneapolis concluded that "wind-induced cable vibrations" were to blame.

The full report is due out on June 28, though city and county officials released a summary this afternoon. That summary indicates URS Corp. may not have factored in the force that ultimately compromised the bridge.

"The project summary provides [Wiss, Janney, Elstner Associates, Inc.'s] conclusions that wind-induced cable vibrations caused fatigue cracking in the diaphragm plates resulting in two cable connections fracturing," said a news release.

"Stay cable vibrations (wind induced) were not included in the original design calculations package," the report summary concludes. Even low wind speeds of 5-10 mph were enough to create damaging vibrations, the consultant found.

Opened in 2007, the distinctive pedestrian and bicycle bridge over Hiawatha Avenue in south Minneapolis was closed abruptly in February after the failure. With emergency supports, the bridge was reopened last week.

URS Corp., which performed work on the 35W Bridge before it collapsed, is seeking a $94 million engineering contract related to the Southwest Corridor Light Rail line. Officials with the Metropolitan Council said earlier this week that they wanted to examine the Sabo Bridge report before making a decision on the bid.

"I think the finding is absolutely a cause for concern," said Susan Haigh, chair of the Met Council, adding that it "raises serious questions." Haigh said that the light rail contract decision will be delayed until the Council can perform an extensive review.

"We want to look at the full report," Haigh said. "We want to have our engineers look at it. We want to meet with Minneapolis and Hennepin County. And of course we want to meet with URS. And that will all be part of a report that will come back to the Council before we would take any action."

So what did the vibrations look like? Play the video for an example uploaded by Patrick Valdez to YouTube nearly one year ago.

Summary report on Sabo Bridge