(Note: this story has been updated since it first appeared in print.)
The Duffey Lake Road section of Highway 99 was closed for a significant portion of the weekend after a series of avalanches occurred in the region on Thursday (May 4) and Friday (May 5).
While avalanche control was originally planned for Friday, the road was closed on Thursday (May 4) afternoon following an avalanche.
According to the Ministry of Transportation and Infrastructure (MOTI), the first avalanche covered about 60 metres of road with an average depth of one metre. "Crews were able to clear the debris, and traffic flow was quickly re-established on the highway," said Danielle Pope, media relations with the MOTI, in an email.
However, the second avalanche happened early on Friday morning and it covered 180 metres of the highway with a maximum depth of 15 metres, which was the largest amount ever recorded on the Duffey. That slide took two days to clear up.
“Long story short: dynamic conditions up there,” read a post on the SLRD’s Facebook page.
Although summer temperatures are slowly beginning to creep into the valley, incidents like these are serving as a reminder that winter risks are still present in the region.
The considerable snowpack remaining in the alpine coupled with rising temperatures can lead to hazardous conditions in the backcountry, explained Avalanche Canada’s warning service manager Karl Klassen.
“When you have a snowpack like we have now and the conditions are like this, even where there’s no snow down in the valley bottom, there’s still an avalanche hazard from above,” he said.
While Avalanche Canada does not continue to provide daily avalanche forecasts during the spring and summer months, there are still a variety of ways to check the risk level of an avalanche before heading out, Klassen said.
“We don’t have any data. We need information from the mountains to make a forecast and people have stopped going into the mountains.
The professional community — that’s our primary data feed — stops working in the mountains. We just don’t have enough information to make a credible forecast,” he said, adding that Avalanche Canada does continue to post information about general weather and conditions on their website.
However, Avalanche Canada’s mountain weather forecasts and on-mountain weather stations are still a good resource help backcountry enthusiasts plan their trips when it comes to temperatures, Klassen added.
“Springtime is really about recognizing when you’re in avalanche terrain and the timing,” he said. “Generally speaking, in the spring, when it’s warm and sunny and the snow’s getting wet, that’s when you’ve got to start watching out and you want to start moving out of avalanche terrain. When it’s cold and frozen and the snow is hard, it is, generally speaking, quite a bit safer.”
Klassen adds that mornings are typically a safer time to travel in the backcountry following an overnight freeze, though warmer days where there was no overnight freeze can yield a much higher risk of avalanche.
For more information on avoiding spring avalanches, go to https://www.avalanche.ca/blogs/spring-avs-hit-valley-bottom-20170504