Avalanche Forecast
Issued: Jan 12th, 2013 8:38AM
The alpine rating is Persistent Slabs and Wind Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Good
Weather Forecast
Sunday: Mainly sunny with cloudy periods in the afternoon. Temperatures should remain cool with alpine highs near -6. Winds are moderate from the northwest. Monday: Mainly sunny with possible valley fog. An above freezing level develops through the day between 1500 and 2500 m. Winds are moderate to strong from the northwest. Tuesday: Mainly sunny with possible valley fog. The above freezing layer strengthens with alpine temperatures rising to +5. Winds are moderate to strong from the northwest. Â
Avalanche Summary
There was a size 2 accidentally triggered slab avalanche in the Spearhead Range on Thursday. A thin wind slab was triggered near ridge top on a relatively low-angle slope, which then stepped down to a weak layer approximately 100 cm deep lower on the slope. This avalanche is suspected to have released on the early January surface hoar layer.
Snowpack Summary
The snow surface consists of thin new wind slabs, a sun crust, dry snow, or feathery surface hoar depending on aspects and elevation. Below this 40-70 cm of storm snow sits on a weak layer of surface hoar, facetted snow, and/or a crust. Snowpack tests on Wednesday continued to yield easy to moderate sudden planar, or "pops", results on this interface. No significant weaknesses have been reported recently below this in the mid snowpack layers. Near the base of the snowpack, a crust/facet layer exists, which is now unlikely to be triggered, except perhaps by heavy triggers in steep, shallow, rocky terrain where more facetting has taken place.
Problems
Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 13th, 2013 2:00PM