Avalanche Forecast

Archived

Dec 13th, 2022–Dec 14th, 2022

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

South Rockies, Bull, Crowsnest North, Crowsnest South, Elkford East, Elkford West.

Wind slabs may remain reactive to rider triggers and a buried weak layer looms in the west and central parts of the region. Check out our latest blog for ways of managing persistent avalanche problems.

Confidence

Moderate

Avalanche Summary

While recent avalanche activity in the region has been limited to explosive triggered wind slabs size 1-2 in the east of the region, backcountry observations have been limited so far this season. If you do go out in the mountains, please consider contributing to the MIN.

In the neighboring regions where the November weak layer is buried deeper, reports of rider-triggered avalanche activity on this layer have been piling up daily. Unfortunately, this is more likely than not a sign of what is to come for the western parts of the region.

Snowpack Summary

20 cm of recent snow has been redistributed by previous strong westerly winds, forming wind slabs at most elevations. Soft snow may still be found in sheltered areas.

A concerning weak layer consisting of facets and surface hoar formed in November is now buried 45-65 cm deep. This layer has been producing large avalanches in neighboring regions and has shown reactivity in snowpack tests here. This one is definitely on our radar!

The lower snowpack consists of sugary and faceted snow, with a thick rain crust near the ground.

Total snowpack depths at treeline elevations are 75 to 155 cm.

Weather Summary

Tuesday night

Flurries bringing a trace of snow. Light northerly wind. Alpine low -13 C.

Wednesday

Flurries in the morning bringing a trace of snow then clearing in the afternoon. Light northerly wind. Alpine high -6 C.

Thursday

Sunny. Light northerly wind. Alpine high -9 C.

Thursday

Mostly sunny. Wind increasing to strong from the northwest. Alpine high -10 C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Keep your guard up at lower elevations. Wind slab formation has been extensive.
Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.

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.