In the past week there have been two fatal avalanche accidents outside the current operating boundaries of Whistler and Blackcomb. These and other recent avalanches in the Whistler area occurred because of an unusual deep instability at the base of the snowpack. This base condition combines crust and facet (loose sugary snow) layers which resulted from the late snowfall and cold weather of this early winter.
After the winter of 1979 I left the snow safety program at Whistler Mountain to work as a snow avalanche consultant. That work has taken me to many different mountain ranges in the world including the Canadian Rockies where I now live. Our snowpack here in the Rockies is typically shallow and weak relative to the deep snows of Whistler. Many a good skier and boarder have left the Rockies to go to Whistler and enjoy the deep snow and steep lines.
About once every 10 years an unusual snowpack with a deep persistent instability comes to the Coast Mountains. The conditions this year are even more unusual. I don't think the conditions have been this tricky in the Whistler area since the low snow winter of 1979 when we saw widespread avalanches at the base of the snowpack through much of the winter.
Whistler has a tremendous
number of very good and very aggressive skiers. These skiers and boarders are
used to seeing lots of snow and avalanches in the backcountry. Those avalanches
typically happen on the surface and are more predictable than the avalanches
Whistler is currently seeing with this deep-seated instability.
No matter who you are,
you are never that good that you can out-guess Nature. When avalanches happen
in these deep-seated instabilities the whole slope will go down very quickly
and it can happen in areas that typically don't see avalanche activity. Remote
triggering (an avalanche on a distant slope triggered from somewhere else in
the terrain) is also common. Cornices and snow mushrooms that you might have
stood on in past years while you were scoping out a line or looking for a place
to jump off will crumble this year because they just don't have any strength where
they are anchored to the rock.
The teams working on the
mountains will get through this. They will move slowly and test things again
and again. Terrain will be opened slowly once the avalanche hazard is reduced.
There is still the
potential for 2009 to turn into a good old fashioned Whistler winter. If
Whistler gets a lot of snow conditions will improve over time. Avalanches will
clean out the instabilities, and the pressure and weight of the snow combined
with a warmer snowpack will start to strengthen the layers below.