Avalanche Forecast
Issued: Nov 29th, 2013 8:00AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
danyelle magnan,
Parks Canada
A new surface hoar layer is now shallowly buried. Avalanche danger will increase as it gets buried deeper. If snowfall amounts are greater than expected on Saturday, avalanche danger will be higher than forecast.
Summary
Weather Forecast
The weather is changing as a low pressure system moves in. Light flurries, temps from -1 to -10, and light to moderate W'ly ridge winds are expected today. Sat will be similar with up to 4cm of snow. Intense snowfall is expected on Sun with strong W'ly winds; avalanche danger will increase. On Mon, temps will begin to drop as arctic air moves in.
Snowpack Summary
Light snow overnight has covered a new surface hoar layer, steep solar aspects a sun crust, and ~10-20cm of surface facets in most areas. These layers will be worth watching if we get lots of snow over the weekend. The Nov 12 surface hoar layer is down 40-100cm, produced very large avalanches during the last storm, and still lurks in many areas.
Avalanche Summary
No new natural avalanches were observed yesterday. The Avalanche Control Section conducted a start of season shoot yesterday, sighting in the howitzers on two targets. Macdonald gully 10 produced a size 1.5 which ran into the fan, and Crossover produced a size 2.5 which stopped in the path.
Confidence
Problems
Persistent Slabs
A widespread surface hoar layer, responsible for several very large avalanches in last weeks storm, still exists in many areas. It is buried by a variety of layers, including soft slabs and facets, and continues to be reactive in snowpack tests.
Dig down to find and test weak layers before committing to a line.Avoid convexities or areas with a thin or variable snowpack.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 30th, 2013 8:00AM
