http://www.pc.gc.ca/apps/links/goto_e.asp?destination=http://www.facebook.com/MRGnationalparks/posts/608542575941919We're in a pattern of stable clear weather but the weakness in our snowpack is still present. Certain areas may not indicate this instability but rest assured that this weak layer is reactive and that cautious route selection is required.
Weather Forecast
High pressure ridge and a northerly flow is settled in over the Province. Cold temperatures, clear skies and moderate northerly winds will be par for the course for the next few days.
Snowpack Summary
Upper snowpack is settling snow. The widespread and highly reactive Dec 17 surface hoar layer is down beneath a ~50-70cm slab and on top of a thick rain crust up to 2100m. The Dec 9 surface hoar is down ~ 70-90cm but is more spotty in distribution. The Nov 9 crust sits 30cm above the ground.
Avalanche Summary
Yesterday, several ski cuts, size 1 and whumphs observed by the field team on Mt Abbott between 1800-2000m. Backcountry report from Hospital Knob area in Connaught of several skier triggered and remote avalanches to size 1.5. Daily reports of rider triggered avalanches to size 2.0 over the last week all down ~50cm on the Dec 17 surface hoar.
Confidence
Due to the number and quality of field observations
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.