Intense ridge top transport observed today in the alpine. This Northwesterly wind will likely have produced some new windslabs, particularly on South aspects.
Weather Forecast
Temperatures to warm slightly before dropping again to -30 by Friday. No precipitation. Northwest winds to continue, making the alpine feel even colder. The intense ridgetop winds are expected to decrease in the next 48hours.
Snowpack Summary
Ongoing moderate Northwest winds redistributing cold snow, soft slab formation possible on lee features. Arctic cold temps have penetrated the shallow snowpack and are promoting facetting. Nov12 crust down 45 to 90cm and found between 2100-2600m on all aspects. Intense ridge top transport from the North reverse loading lee features in the alpine.
Avalanche Summary
Numerous loose dry avalanches on Westerly aspects up to Size 2 in Alpine terrain observed along the Icefields Parkway today. Recent shift of winds to the Northwest seem to have been the trigger for these events. One remotely triggered slab avalanche size1.5 was reported from the Boundary Glacier area on Monday, 2400m steep East facing planar slope.
Problems
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
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.