Avalanche Forecast
Issued: Feb 3rd, 2015 8:41AM
The alpine rating is Storm Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeNew snow continues to add to the developing storm slab. The next Pacific storm should arrive on Thursday.
Summary
Confidence
Fair - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
A chance of light flurries overnight and during the day on Wednesday combined with moderate Southwest winds and temperatures around -10 in the alpine. The next storm should hit the coast early Thursday morning and then quickly move inland where it is expected to collide with the arctic air descending from the North. Expect 5-10 mm of precipitation that may be 10-20 cm of snow combined with strong Southwest winds and alpine temperatures which may be warmer than the valleys as the warm Pacific air moves over the cold arctic air. Expect another 8-12 mm of precipitation that may be 15-25 cm of snow by Friday morning and another 10-20 cm during the day. The storm should continue through Saturday.
Avalanche Summary
There were numerous small size 1.0 Loose dry and soft storm slab avalanches releasing at the storm snow/crust interface, or pockets of wind transported snow at ridgetops.
Snowpack Summary
The new storm slab is 30-50 cm and sits on a variety of old surfaces. A crust can be found below about 1900m in the north of the region and below 2200m in the south of the region. At higher elevations the new snow covers old wind slabs formed by moderate southwest winds. Several persistent week layers can be found deeper in the snowpack that may be capped by the overlying crust at lower elevations. The mid-January surface hoar is buried between 40 and 80cm down and remains a concern at treeline and above. The mid-December surface hoar layer is now 80 to 140cm below the surface and appears to be slowly gaining strength.
Problems
Storm Slabs
Recent storm snow may have settled into a soft slab above the old surface crust and/or a new layer of surface hoar. Fracture propagation may increase as the new storm slab settles.
Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Avoid freshly wind loaded features.>
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
The mid-January weak layer may continue to be triggered in some areas where the buried crust and surface hoar combination still exists. This may be isolated to terrain that remained cold during the warm up last week.
Choose well supported terrain without convexities.>Carefully evaluate and use caution around thin snowpack areas.>
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 4th, 2015 2:00PM