Avalanche Forecast
Issued: Dec 10th, 2011 8:54AM
The alpine rating is Wind Slabs and Storm Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - Intensity of incoming weather is uncertain on Monday
Weather Forecast
Sunday: Scattered cloud, trace amounts of snow and light northwesterly winds Monday: 10-15 cms of snow combined with strong southwest windsTuesday: Moderate snowfall with moderate northwest winds for the morning. Clearing expected for the afternoon.Freezing levels expected to sit at or around surface for the forecast period.
Avalanche Summary
No avalanche activity has been reported. Expect widespread activity with current conditions and forecast weather.
Snowpack Summary
Between 10 and 20 cms of snow combined with strong to extreme westerly winds arrived on friday night.In some parts of the region, light amounts of new snow had previously buried large surface hoar that was sitting on a 5-20cm thick melt freeze crust. This crust extends into alpine elevations in the south, and around 1000m in the north. A strong temperature gradient in the top 30cm was reported to be faceting snow below the surface crust. The mid and lower snowpack are generally well settled and strong.At this point I have a few concerns: Because of the intensity of friday night/saturday morning's winds, the surface hoar may have been destroyed in some areas, but probably still exists in others. This makes it difficult to track now that the new snow is hiding it. As well, with the higher winds the distribution of the new wind slab may be less predictable and you are likely to find loading lower on the slope than usual. The new slab will also have varying propagation characteristics. For example, in areas where it is wind-affected and stiff, it will be likely to slide; however, you might not see the same reactivity at lower elevations or on the eastern fringe of the region where there may not have been as much wind.Regardless of all the speculation, there has been moderate snowfall with a ton of wind and it's sitting on a melt-freeze crust in a major portion of the region. There is also more on the way on monday, so you can expect widespread reactive windslabs for the the forecast period.
Problems
Wind Slabs
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 11th, 2011 8:00AM