As of Wednesday, March 3 1999
More snow has continued to fall during the past week. The total snowfall at 1,650m. on Whistler Mountain for the month of February was a whopping 450 cm — one of the snowiest months on record.
Another 30 cm of snow has fallen since yesterday afternoon, accompanied by moderate to strong mountaintop winds from the ESE. This was some of the lightest snow we have ever seen here. The high winds and zero visibility prevented us from assessing the high alpine today, but soft slabs up to 60 cm in depth were observed to be easily triggered on lee slopes between the 1,850m and 2,050m elevations.
The snowpack is continuing to settle at a rapid rate, a fact that has not gone unnoticed by anyone trying to break a fresh trail. The constant storm winds have made for extremely variable conditions. In most alpine locations, in the upper 100 cm of the pack you will find at least one softer layer that is sandwiched between two harder layers. The soft layer may represent a period when the winds abated or the temperature cooled, and the continuing snowfall kept it insulated and more resistant to settling. In many areas the overlying slab has enough strength to bridge over the weakness. If the weakness is closer to the surface, however, it may be more easily triggered.
During the course of explosive testing carried out this week, we have also been seeing step fractures occurring. The slab was initiated in the surface new snow, but pulled down into one of the softer layers in the storm snow.
The cornices have become huge and are pulling back onto the flats when they fail. Stay well away from the edge. If your route forces you to traverse under a corniced ridgeline, make sure that no one else is above you, poised to inadvertently kick off a refrigerator sized chunk.
Don’t be lulled in by our seemingly uneventful snowpack. With the large amount of snow that has fallen lately, there have got to be some lurking surprises out there. Always follow the basic safety rules for travel in avalanche terrain, regardless of how "bombproof" you may perceive a slope to be. Remember that the avalanche doesn’t know or care that you are an expert!
The long-range weather forecast is calling for a cool, unstable onshore flow to provide us with light accumulations of snow fall Thursday, Friday and Saturday. The next organized system is forecasted to arrive in our region sometime on Sunday.
The Backcountry Avalanche Danger is rated as HIGH as of March 3. Check for the most current information before you head out. Call 938-7676 for the conditions in the backcountry adjacent to the Whistler/Blackcomb ski areas.