A leading expert says there's no way to prevent "ice bombs" from falling off of bridge cables and on to the cars below, and a similar situation is possible when the bridge replacing the Massey Tunnel is built.
The Alex Fraser Bridge was temporarily closed on Monday and Saturday due to a risk of falling snow and ice, and at least 145 insurance claims have been filed by drivers whose windshields were struck by the "ice bombs" as they passed over the Alex Fraser and Port Mann crossings.
The bulk of the damage was caused on the Alex Fraser, which came as a surprise to the provincial government as the bridge's cables don't hang over the roadway. Falling snow has also been reported on the bridge a couple of times over the years, however, in 2005 and 2008.
The Port Mann Bridge, which is the source of 50 of the 145 insurance claims, has snow-clearing collars on each of its 288 overhanging cables. The collars were installed after an "ice bomb" fiasco in 2012, which damaged about 350 vehicles.
The government is characterizing the most recent storm on Monday as a freak weather event: a system dumping far more snow than expected, a flash freeze and then a sudden thaw.
"Those cables jumped from -5 to 5 very quickly and that caused the snow to release very quickly," said executive director of BC Highway Operations Norm Parkes.
"We have very good weather forecasting, but weather forecasts aren't always correct."
But an expert said the bridges should be closed ahead of time, and officials with the Ministry of Transportation should have seen it coming.
Christos Georgakis, an engineering professor from Aarhus University in Denmark, was the main external consultant on the Port Mann Bridge problem four years ago.
He said there's not really a solution that adequately solves the problem.
"There is no silver bullet here," Georgakis said. The best thing the ministry can do is watch the weather, and close the bridges if the forecast suggests problems are on the way.” He said he knows drivers will find the closures frustrating, but that it's better than the alternative of being struck by falling snow or ice.
"In my opinion shutting down the bridges for some hours or half a day once every four, five, six years was not catastrophic," he said.
"We're trying to fight nature when we shouldn't be trying to fight nature."
But Minister Todd Stone told CTV News on Tuesday that a full closure is "very unlikely" on either of the bridges because of "the additional measures we have in place."
Stone also said crews are taking lessons learned from incidents in the past, as a way to prevent them from happening again with new bridges like the one that will replace the Massey Tunnel.
"We intend on doing everything we can to get to a place where these incidents don't happen at all on our crossings in British Columbia," he said.
Georgakis doesn't think it's possible in a city where snowfall is inevitable in the winter.
"It doesn't matter that the cable planes are not over the bridge. It doesn't matter that chains and collars have been put on the stays. These things will happen," he said.
"The problem will still be there. We have a structure out in nature exposed to the elements. How can you stop snow and ice from accreting on it? It's just not possible."
With a report from CTV Vancouver's Scott Roberts
