Avalanche Forecast
Issued: Feb 5th, 2013 9:42AM
The alpine rating is Wind Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - Due to limited field observations
Weather Forecast
Wednesday: Expect mostly cloudy skies with a chance of flurries. Winds should be light southerly and alpine temperatures should reach -7.Thursday: We should see a mix of sun and cloud with winds turning westerly then northwesterly and strengthening. Very isolated flurries are possible. Alpine temperatures should reach around -8.Friday: Clouds return with a slight chance of flurries. Winds settle back to westerly and increase to moderate values. Expect temperatures around -7.
Avalanche Summary
A natural cycle has passed with windslab avalanches at treeline and in the alpine up to size 2.5 and loose wet sluffing at lower elevations.
Snowpack Summary
Up to 40cm of recent storm snow has fallen in the past 72 hrs. Consistent southwesterly winds have maintained snow transport, and many lee zones show layers of windslab over windslab. The deepest storm interface (from the very beginning of this storm cycle) includes a huge variety of old surfaces from facets to crusts and isolated pockets of surface hoar (sheltered treeline and below treeline). There is very limited information with regards to this interface, with the only results suggesting reactivity in sheltered, shady treeline and below treeline slopes (likely associated with the preserved surface hoar pockets). I would stress the importance of digging down to find and test weak layers. A cautious and curious approach is critical.At low elevations (below 800m) the recent storm snow is still moist below the surface. Wet slabs at low elevations may still be possible in steep convex features.The strong mid-pack overlies a weak base layer of facets/depth hoar. Triggering of this basal weakness may still be possible from thin spots, rocky outcrops or under the weight of larger triggers such as cornice fall.
Problems
Wind Slabs
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 6th, 2013 2:00PM