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

Mar 4th, 2025–Mar 5th, 2025

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

Regions

Purcells, Esplanade, Dogtooth, East Purcell, St. Mary, West Purcell.

New snow & wind may form reactive wind slabs near ridgetops.

Remain especially cautious on high northerly slopes & areas without a thick supportive crust under the new snow.

Confidence

Moderate

Avalanche Summary

Mon: A few small size 1 wind slabs and sluffing were observed.

Sun: A few persistent and loose wet releases size 1-2, with both human and natural triggers occurred.

Sat: Many natural, remote, and explosives-triggered slabs failed on the late-Jan layer, generally sized 2-3 from upper elevations.

Fri: A skier was caught in a size 1.5 slab and partially buried.

Looking forward: Wind slabs may be reactive and have potential to step down to deeper layers on Wednesday.

Snowpack Summary

Up to 5 cm of new snow is expected overnight and Wednesday morning, adding to the 2 - 10 cm of snow the region saw on Monday. This new snow buried a widespread melt-freeze crust that exists everywhere but high north-facing slopes. In wind sheltered areas it may have buried a new layer of surface hoar. A couple of weak layers consisting of a crust, facets or surface hoar from February and January remain a concern, buried 30 to 60 cm. Additionally, a layer of facets from early December is buried 70 to 120 cm. In many areas, facets or depth hoar exist at the base of the snowpack. These layers, particularly the late-January layer, remain a primary concern at upper elevations where strong surface crusts are absent.

Weather Summary

Tuesday Night

Cloudy with 0 to 5 cm of snow. 5 to 10 km/h southwest ridgetop wind. Freezing level 1600 m dropping to valley bottom. Treeline temperature dropping to -5 °C.

Wednesday

Mainly cloudy with 0 to 3 cm of snow. 10 to 15 km/h southwest ridgetop wind. Freezing level rising to 1600 m. Treeline temperature around -4 °C.

Thursday

A mix of sun and cloud. 10 km/h north ridgetop wind. Freezing level rising to 1600 m. Treeline temperature around -4 °C.

Friday

A mix of sun and cloud. 5 to 10 km/h west ridgetop wind. Freezing level rising to 1700 m. Treeline temperature around -2 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be aware of the potential for large, destructive avalanches due to deeply buried weak layers.
  • Avoid steep, rocky, and wind-affected areas where triggering slabs is more likely.
  • Use ridges or ribs to avoid areas of wind-loaded snow.
  • Keep in mind that human triggering may persist as natural avalanches taper off.

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.