Strong winds have formed windslabs in the alpine. The cold temperatures have weakened the surface snow somewhat, and thus weakened some bridging of the snowpack. PW
Weather Forecast
Temperatures will remain cool tonight and tomorrow with a high tomorrow of -10 at ridge top, but we are leaving this mini arctic flow and will be gradually getting warmer temps to where the freezing level may reach 2000m by Saturday.
Avalanche Summary
A couple of solar induced sluffs were noted in steep rocky terrain. One avalanche of note occurred on Tent Ridge, in one of the gullies mid-ridge. It is estimated to be a size 2.5 which is large considering the lack of natural activity recently. Check out our Kananaskis Public Safety Facebook page for a picture of the Tent Ridge avalanche.
Snowpack Summary
An average of 10cm of snow fell throughout the region, but amounts vary from drainage to drainage. This has not changed hazard levels below treeline, but at treeline and in the alpine this is a different story. Strong north westerly winds up high moved snow around all day, and by mid-day the winds started to affect treeline elevations as well. Widespread soft slabs exist on lee aspects in the alpine, and are just starting to form at treeline elevations. The sun packed a punch today and on steep solar aspects the snow almost became moist, even though temperatures were below freezing all day. Cold temps overnight (-30degC at Mud Lake) contributed to near surface facetting, which remains on polar aspects.
Problems
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.