Parkers Upper telemetry indicates since 8pm Saturday, winds blowing steady SW 20-60km/hr gusting 90. Other stations also increasing wind values. Prime windloading conditions. Expect changing conditions and increased likelihood for natural activity.
Weather Forecast
Jet stream lies over BC bringing strong NW alpine winds for next couple of days. 2 systems will bring continuous yet light snow with potentially more amounts in the Icefields. A snow warning exists just to the West which may trickle into the Icefields area. Milder temperatures are expected next couple of days and reduced winds by Tuesday.
Snowpack Summary
Moderate gusting strong swirling alpine winds are transporting the available 20cm or more of surface snow. Expect variable loading patterns with local terrain influences. Saturday's snow pit above Parkers Slabs was 190cm thick on a well settled mid pack. Whatever was on the surface is likely getting redeposited. Still overall variable snow depths.
Avalanche Summary
Saturday three size 2-2.5 avalanches were noted now 48-72 hours old, 40 degree plus, NW aspect, cross loaded gullies. Thursday' s explosive work on parkers slabs with 22 avalauncher rounds produced one size 2 slab avalanche in a wind loaded location on smooth steep rock slab. Patrol South today had limited visibility but swirling winds encountered.
Confidence
Wind effect is extremely variable
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.
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.