The best riding is in sheltered areas with low density snow, but watch for shooting cracks and whumpfing sounds as indicators of a developing persistent slab problem.
Confidence
Moderate - Due to the number and quality of field observations
Weather Forecast
SUNDAY: Sunny with increasing clouds and light flurries overnight, gusty northwest winds, treeline temperatures around -18 C.MONDAY: Mix of sun and cloud, light northwest winds, treeline temperatures around -22 C.TUESDAY: Mostly sunny, strong northwest winds, treeline temperatures around -20 C.
Avalanche Summary
Some small natural dry loose avalanches were reported in steep alpine terrain on Saturday. Some larger slab avalanches were triggered with explosives immediately after last week's storm on Friday (up to size 2).
Snowpack Summary
Cold temperatures are preserving fresh snow from the past week, with up to 80 cm in southern and eastern parts of the region and 50 cm in the Elk Valley. The snow has been deposited into harder wind slabs in exposed terrain, but remains low density in sheltered areas.The main question in the snowpack surrounds the layer sitting beneath the new snow. The layer includes old crusts, wind scoured surfaces, and large feathery surface hoar crystals in sheltered terrain at and below treeline. The distribution of the layer, as well as the properties of the snow above it, is highly variable. The most suspect areas are where the wind has formed a stiff slab above this layer and on slopes with preserved surface hoar.Two crusts that were buried near the end of November can be found lower in the snowpack. A third crust from the end of October exists near the base of the snowpack. Recent testing on these crusts have not produced significant results.
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.
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.