Avalanche Forecast
Issued: Feb 21st, 2014 8:31AM
The alpine rating is Persistent Slabs and Storm Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - Timing or intensity of solar radiation is uncertain on Sunday
Weather Forecast
Some light disturbance is expected for Saturday and Sunday as a ridge of high pressure builds. Clear, cold, and dry conditions are expected for Monday once the ridge of high pressure has established. Saturday: A mix of sun and cloud, light scattered flurries 0-1cm, treeline temperatures around -10C, ridgetop winds light NWSunday: A mix of sun and cloud, light scattered flurries 0-2cm, treeline temperatures around -15C, ridgetop winds light NWMonday: Clear and sunny, treeline temperatures around -13C, ridgetop winds light NW
Avalanche Summary
Natural avalanche activity is generally decreasing now that the storm has ended but we are still receiving reports of natural activity. Conditions are ideal for human triggering right now and we have received numerous reports of skier triggered avalanches, many of which have released quite deep in the snowpack. Several of these avalanches were remotely triggered. On Thursday, 2 remotely triggered avalanches and 1 skier controlled avalanche were reported in the Purcells. The largest of these was a size 2.5, the farthest trigger was 75m away, and the deepest was 80cm. Early reports suggest an avalanche accident involving 1 or more people may have occurred on Friday near Golden.
Snowpack Summary
The recent ten-day storm has produced a cohesive slab that averages 40-90 cm in thickness. This slab sits on a nasty persistent weak layer (surface hoar/facet/crust combo) that was formed during the preceding month of cold, dry weather. This weak layer is widespread at all elevations and aspects, and is creating problems even in previously skied terrain. Large settlements and whumpfs have been reported at all elevations. We have received numerous reports of remotely-triggered avalanches from as far as 200m away which indicates a high likelihood of large propagations within the weak layer. We expect touchy conditions to remain in place longer than we're normally accustomed to. Recent strong winds out of the SW through NW have created wind slabs on leeward features in wind exposed areas at treeline and in the alpine. In many areas, thick wind slabs may overlie the persistent weak layer creating conditions for very large avalanches.Weak basal facets exist in some areas, but triggering has now become unlikely. For the most part, the mid and lower snowpack are strong and well consolidated.
Problems
Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Storm Slabs
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 22nd, 2014 2:00PM