Avalanche Forecast

Archived

Nov 20th, 2015–Nov 21st, 2015

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Regions

Cariboos.

Given the very limited information on hand for this bulletin, I would ride cautiously this weekend and take the time to gather snowpack information as I go. As always, we would love for you to submit any observations from your day to the MIN.

Confidence

Fair - Due to the number and quality of field observations

Weather Forecast

Isolated flurries are expected for Saturday and Sunday before the snowfall intensifies on Monday when up to 20cm of snow is possible. Freezing levels will rise to around 1000m with an inversion developing overnight on Saturday. A cooling trend is expected with the arrival of the storm on Monday. Winds will be mainly light to moderate from the west throughout the forecast period.

Avalanche Summary

The storm earlier in the week resulted in a widespread avalanche cycle that produced some large avalanches.

Snowpack Summary

Up to 50cm of new snow fell in the last week. Below this new snow we’re dealing with a complex snowpack. Previously fickle wind, changing freezing levels and varying snowfall amounts mean that conditions could change dramatically with aspect and elevation. Layers of buried surface hoar or crusts may be found depending on where you dig. It would be wise to test these layers before committing to a slope. At higher elevations in the alpine, facets may be found above the ground, especially on north aspects.Remember that although it's starting to look like winter, it’s still a thin snowpack. Rocks and stumps may be lurking unseen just below the surface. Ride with care!

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.