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

Feb 22nd, 2022–Feb 23rd, 2022

Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

Kootenay Boundary.

Recent northeast winds have cause reverse loading and built slabs in unexpected features. Watch for pockets of wind slab on various aspects in exposed terrain and around ridge lines.

Confidence

Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.

Weather Forecast

TUESDAY NIGHT: Clear with moderate northeast winds. Alpine lows of -22. 

WEDNESDAY: Sunny with increasing cloud late in the day, winds easing to light from the northwest. Alpine high of -11. 

THURSDAY: Mix of sun and cloud, light northerly winds and alpine high of -7.

FRIDAY: Partly cloudy, light northwest wind and high of -8.

Avalanche Summary

On Monday there were several size 1-1.5 wind slabs triggered by skiers as well as a few natural wind slabs spotted in the backcountry. There was also a size 2 avalanche that was triggered remotely by someone walking on a ridge top, that failed on a surface hoar layer buried in late January. A Mountain Information Network post also reported a cornice failure that triggered a small slab.

Snowpack Summary

Recent northeast winds have be scouring and wind affecting open areas and forming wind slabs in lee terrain. This reverse loading means there may be wind slabs in unusual locations. In sheltered locations there is likely around 20-40 cm of snow over an old February drought layer interface that consists of various melt-freeze crusts and old wind-pressed snow depending on your elevation and aspect.

Two layers of buried surface hoar sit in the upper snowpack, most likely to be found and triggered in sheltered areas at treeline. These are now down around 30-50 cm and 60-80 cm deep. Though improving, these layers remain reactive in some snowpack tests and have been responsible for sporadic avalanches, including a size 2 triggered remotely from a skier walking on a ridge top yesterday.

The lower snowpack is well consolidated, with a crust/facet layer found 100 to 200 cm deep. It is currently considered dormant, but could become active later this season. Check out the forecaster blog for more information. 

Terrain and Travel

  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Watch for newly formed and reactive wind slabs 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

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.