Travel conditions are improving as last week's storm snow settles into a supportive midpack. The main concern is the interface between this settled snow and crusts near the bottom of the snowpack, particularly at treeline.
Weather Forecast
Temperatures to remain mild throughout the week, dropping next Sunday. We expect 5cm in the Icefields area in the next 24 hours and then another 15cm over the course of the week. A steady drop in pressure and cloudy skies throughout the week will accompany the snowfall. Winds will be variable; most intense mid-week from the South.
Snowpack Summary
Settled storm snow at lower elevations and windslab in the alpine. The main concern is the interface between the settled storm snow and several crusts near the bottom of the snowpack. This interface is producing sudden collapse results in test profiles and widespread whumphing at treeline and has been associated with recent natural avalanches.
Avalanche Summary
Field teams reported several full depth avalanches to size 2 on South East aspects at approximately 2400m. These occurred in the last 24 hours.
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.