Regions
Banff Yoho Kootenay.
We are in a holding pattern until more snow and wind arrive Saturday. This means natural avalanches aren't occurring on a regular basis, but we still lack confidence in the current snowpack to step out into bigger terrain. SH
Weather Forecast
Only a couple cm of snow Friday with increasing Westerly winds and alpine temperatures rising slightly but staying in the -6 to -10C range. Another 5-10cm forecast for Saturday and strong alpine winds.
Snowpack Summary
Wind slabs in alpine and tree line areas are now stubborn to trigger. The Jan 6 surface hoar/facet/sun crust layer, down 30-60cm, has becoming less reactive to skier triggering, however sudden collapse results persist on both the Jan 6 and Dec 3 layers. Isolated whumphing on mid-pack facets/surface have been observed this past week.
Avalanche Summary
No new avalanches were reported over the last 24 hours.
Confidence
Forecast snowfall amounts are uncertain on Saturday
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.