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 30th, 2021–Dec 31st, 2021

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

Regions

North Rockies.

Assess for wind slabs, which could be triggered in steep terrain.

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

THURSDAY NIGHT: Partly cloudy with no precipitation, 10 to 20 km/h northeast wind, alpine temperature -23 C.

FRIDAY: Partly cloudy with no precipitation, 10 to 20 km/h northwest wind, alpine temperature -21 C.

SATURDAY: Cloudy with snowfall, accumulation 5 to 10 cm, 60 to 90 km/h southwest wind, alpine temperature -14 C.

SUNDAY: Cloudy with snowfall, accumulation 5 to 15 cm, 20 to 40 km/h southwest wind, alpine temperature -13 C.

Avalanche Summary

No recent avalanches have been observed in the North Rockies.

We'd appreciate if you submit your observations to the Mountain Information Network, even just a photo.

Snowpack Summary

Wind slabs may have formed from Wednesday night's 5 cm of snow and strong wind from variable directions. These slabs could remain touchy to riders, as they sit on previously wind-affected snow, sugary faceted grains, and/or surface hoar in areas sheltered from the wind.

A weak layer of feathery surface hoar may be found around 20 to 50 cm deep. It is most likely found in sheltered terrain features in the lower alpine and treeline, or open features below treeline (e.g., cut blocks). We've only received a few reports of this layer, so it may be spotty in the region.

The middle of the snowpack has been reported as well-settled and strong. The base of the snowpack is composed of weak faceted grains, particularly in thin snowpack areas east of the divide, but has not recently been a concern.

Terrain and Travel

  • Carefully evaluate steep lines for wind slabs.
  • Make observations and assess conditions continually as you travel.

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.