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

Jan 14th, 2024–Jan 15th, 2024

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

Regions

Purcells, Dogtooth, East Purcell.

Deep instabilities are best managed through conservative terrain selection.

Be aware that variable winds have built wind slabs in atypical areas. Use caution in wind-affected areas.

Confidence

Moderate

Avalanche Summary

Through the weekend riders reported seeing sign of instability such as cracking when transitioning into wind-affected areas. A few natural and skier-triggered, size 1, dry loose avalanches were reported in steep terrain.

On Friday a size 2.5, natural slab avalanche was observed from a distance on a south-facing alpine slope near the Silent Pass area.

If you go out in the backcountry, please consider sharing your observations on the Mountain Information Network (MIN).

Snowpack Summary

Up to 40 cm of recent, low-density snow has both been pressed and redistributed due to wind effect. This recent snow is found sitting atop a variety of old surfaces, including surface hoar, crusts and/or facets.

The mid and lower snowpack is generally weak with several layers of note. Of greatest concern are weak facets and/or depth hoar located at the bottom of the snowpack, particularly in alpine terrain.

Snowpack depths at treeline range from 60 to 150 cm.

Weather Summary

Sunday Night

Clear skies with no precipitation, primarily northwest alpine wind 10 to 25 km/h, treeline temperature -22 °C.

Monday

Mainly sunny with no precipitation, northwest alpine wind 10 to 25 km/h, treeline temperature -16 °C.

Tuesday

Partly cloudy with isolated flurries, trace amounts of snow, west alpine wind 10 to 25 km/h, treeline temperature -15 °C.

Wednesday

Cloudy with scattered flurries, 3 to 7 cm of snow, southwest alpine wind 20 to 30 km/h, treeline temperature -15 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
  • Avoid lee and cross-loaded slopes at and above treeline.
  • 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.

Problems

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.

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.