Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Dec 16th, 2021–Dec 17th, 2021

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

Kootenay Boundary.

We are reaching a tipping point where triggering large, destructive avalanches will become more likely . Where exactly these large avalanches can be triggered will be hard to predict. Read the forecaster's blog to learn more.

Confidence

Low - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.

Weather Forecast

Thursday night: No new snow expected. moderate Northwest winds with a low of -11 at 1500m.

Friday: Sunny with no new snow. moderate Northwest winds becoming light to moderate Southwest in the afternoon. A high of -11 at 1500m.

Saturday: A storm arrives bringing 10 to 40cm of new snow with the greatest snowfall at Kootenay Pass. Strong Southwest winds. High of -6 at 1500m.

Sunday: light winds and no new snow expected. High of -6 at 1500m.

Avalanche Summary

A size 1.5 skier accidental was observed in a part of the South Columbia region that has similar snowpack conditions to the Kootenay boundary. This avalanche failed on the facets above the early December crust which was down 35cm on a North aspect at 2200m.

Snowpack Summary

Up to 10cm of low density snow overlies old variably wind effected surfaces.

The defining feature of the snowpack is a widespread crust that now sits 30-70 cm below the surface. In many places overlying snow is well-bonded to the crust but in others, including Kootenay Pass, weak faceted grains have been observed above it around treeline.  

Snow depths are roughly 140-180 cm at treeline throughout the region.

Terrain and Travel

  • Be careful as you transition into wind affected terrain.
  • Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.

Problems

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.

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.