SPIN checked in to find out more about highway avalanche control programs and what they mean to drivers and backcountry travellers
The Coquihalla Highway runs through mountainous terrain and cuts below over 30 avalanche paths, putting the transportation corridor at risk all winter long.
For commuters, transportation truck drivers and those who choose to recreate in the Coquihalla backcountry, it’s important to know when avalanche control closures could happen and where to find that information.
Benn Andersen, the Ministry of Transportation and Infrastructure’s senior program manager for avalanche and weather programs, told SPIN highway closure can happen suddenly depending on conditions.
“The main place we advertise closures associated with high avalanche hazard is DriveBC,” he said. “We provide notifications for any type of conditions or delay, [DriveBC] is the best place for people to get the heads up on what highways may be closed and when control work is being conducted.”
They typically try to give six to 12 hours of notice for any planned closure but are always at the mercy of Mother Nature. Closures happen on average twice per season however, some years have seen up to five.
“Weather drives the avalanche hazard. If it snows a little more, gets warmer than we’re expecting, or conditions change rapidly, and because avalanche problems are driven by weather, we may not have the ability to provide reasonable notice.”
Steady increases in snowfall are more likely to cause an avalanche control closure than a sudden storm, especially if the state of the changing snowpack indicates certain weaknesses that could result in a high likelihood for an avalanche on a large slope.
Andersen said their avalanche danger ratings are different than those Avalanche Canada put out to the public, as the ministry’s control program is only concerned with slopes that face the highway and change once they have been controlled.
The closures usually last no more than four hours, but have gone as long as four days in one extreme case eight years ago when reduced visibility made it impossible to fly helicopters above the slopes to control them using explosives.
Andersen said he would typically advise backcountry skiers to avoid the avalanche paths they control, which are the ones that face the highway, as they may not provide the best turns.
“Often they’re full of avalanche debris or a lot of them are south facing so conditions aren’t as nice as north or west aspects. We try to discourage folks from recreating within our avalanche areas.”
There are signed areas (pictured) at the summit cautioning people that avalanche control with the use of explosives could occur without warning, although part of the control program’s procedure is to do a sweep of the area via helicopter to make sure areas are clear of skiers and snowshoers.
One closure has already happened this season, but Andersen said the Coquihalla was built in a way to ensure closures would be kept to a minimum as it runs through an area where only very large avalanches would hit.
“The Coquihalla was really well designed. Where it runs is at the maximum extent of the avalanche paths, so we’d need to have a fairly significant avalanche hazard to close the highway,” he said, adding there is one area where a size 2.5 avalanche could affect the highway, and a few other spots where avalanches could happen on shorter slopes. One example is the Coquihalla summit rock bluffs which could deposit snow onto the highway causing a significant risk to drivers.
“There are a few spots on the Coquihalla that may not bury the road but it’s more about how it could result in traffic accidents because somebody may round a corner at 90km/h and bump into a pile of snow one metre deep. We make sure to maintain those.”
To be up to date with control closures or other highway delay notices, Andersen suggested that people sign up for alerts through DriveBC, where individuals can be alerted based on their geographical location of interest. People can also follow @DriveBC on twitter to become notified about delays.
And if you are a backcountry traveller and want to do your part, Andersen said to contribute by reporting your avalanche observations to Avalanche Canada’s Mountain Information Network, as his crew and Avalanche Canada work closely alongside one another.
He added that photographs are extremely helpful within the submitted reports.