Avalanche Forecast
Issued: Dec 29th, 2011 9:24AM
The alpine rating is Persistent Slabs, 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 Friday
Weather Forecast
Friday: Snow amounts 10-15cms. Ridgetop winds 40km/hr from the West. Freezing levels could rise to 1100m. Saturday/Sunday: A ridge of high pressure is expected to move into the region for the weekend. Mainly sunny skies, and light-moderate winds from then NW.
Avalanche Summary
We are now in an avalanche cycle with numerous natural avalanches occurring, reported up to size 3. These occurred on all aspects above 1700m with wide propagations, and crown depths up to 50cms. Many of these are failing on the mid-December surface hoar, mostly on north through east aspects from 1500m to the peaks. A skier remotely triggered an avalanche from 50m away and in many places shooting cracks and whumphing are further indicators of a very touchy, unstable snowpack.
Snowpack Summary
The snowpack is in a very touchy state. 30-50cm of storm snow has built up over a weak old snow surface. The storm snow has turned into a soft slab due to warming. South-west winds have led to the development of wind slabs on lee slopes. The surface hoar layer buried in mid-December is now under 45-70cm of snow and is highly reactive. It is well-preserved with 10-15mm crystals and exists into alpine start zones (although it's probably best preserved in sheltered areas near treeline). The mid-pack is generally well settled. Facets exist at the base of the snowpack.
Problems
Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 30th, 2011 8:00AM