With the deep snowpack in many areas of Western Canada this winter, the snowmobiling season could be a long one for dedicated riders. But as winter finally gives way to spring, sledders are reminded that the threat of avalanches doesn’t end with the arrival of warm weather.
Ilya Storm, forecast co-ordinator with the Canadian Avalanche Centre (CAC), said that although the final avalanche bulletins of the season will be issued on April 23, winter weather can linger a lot longer high in the mountains, and this means snowmobilers may still be heading out into avalanche terrain.
Storm said snowmobilers should make an extra effort to gather information on current conditions after the avalanche bulletins end by sharing observations with other riders in person or through online forums.
He said the good news is that as spring moves into the high mountains, the snowpack typically becomes a lot more predictable, due to warmth seeping deep into the snow and consolidating all the various layers, creating “one big blob of snow.”
A winter snowpack is typically made up of many layers, said Storm, making it more complicated when it comes to determining the potential for an avalanche. With a mature spring snowpack, the constant melting and refreezing of the snow will create one consistent layer topped by a hard crust of 20 to 30 centimetres.
Basically then, Storm said, you know that when the snowpack is frozen after a nighttime of below-freezing temperatures, it is quite strong—and as the snowpack begins to melt from warm daytime temperatures and the sun, it starts to weaken and the threat of an avalanche rises.
The game plan with a spring snowpack, he said, is for snowmobilers to get an early start, enjoy the snow, and then be out of avalanche terrain once the crust and snowpack get too soft.
Storm added that spring brings other hazards to the backcountry that sledders need to be aware of when heading out for some late-season riding. During the transition from winter to spring, cornices start falling, providing natural avalanche triggers on many slopes. Later, creeks begin opening up, crevasses are uncovered on glaciers, and ice on lakes starts to break up.
Storm said when the final avalanche bulletins are posted for the season, the CAC will include information on snow safety during springtime in the backcountry.
The CAC has plenty of resource material on snow safety in general on its website, and a special section provides information of particular interest to snowmobilers.
