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, 2025–Jan 15th, 2025

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

Regions

Purcells, Dogtooth, East Purcell, West Purcell.

Avoid aggressive terrain choices where a persistent slab problem could exist. Steep, rocky, shallow terrain are the most likely trigger areas.

Confidence

Moderate

Avalanche Summary

Two notable avalanches occurred in the Dogtooth Range on Saturday:

  • A skier was caught in a size 2.5 wind slab avalanche that propagated widely across a northeast-facing slope. It ran on a 5 to 40 cm deep surface hoar layer. See this MIN report for details.

  • A group of skiers remotely triggered a size 2.5 persistent slab avalanche on a large southwest-facing alpine slope.

Many smaller (size 1 to 1.5) wind slab avalanches were also reported across the Purcells.

Snowpack Summary

Surface snow is a mix of newly developed surface hoar and sun crust. Wind-loaded pockets exist above various layers of soft snow, surface hoar, and melt-freeze crust.

A weak layer of facets buried in early December is on average 60 to 90 cm deep (except closer to 30 cm in the shallower eastern parts of the Purcells). This layer continues to cause occasional large avalanches.

The snowpack base consists of a thick crust and facets in many areas.

Weather Summary

Tuesday Night

Partly cloudy. 10 km/h west ridgetop wind. Treeline temperature -5 °C.

Wednesday

Partly cloudy. 10 km/h southwest ridgetop wind. Treeline temperature -4 °C.

Thursday

Partly cloudy. Isolated flurries,1 cm. 40 km/h southwest ridgetop wind. Treeline temperature -5 °C.

Friday

Partly cloudy. Isolated flurries 1 to 2 cm. 30 km/h northwest ridgetop wind. Treeline temperature -5 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Avoid steep, rocky, and wind-affected areas where triggering slabs is more likely.
  • Pay attention to isolated wind affected features in the alpine, as well as cross-loaded features at treeline.

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.