Avalanche Forecast
Regions: Dogtooth, East Purcell, Purcells, West Purcell.
Persistent slabs are possible to trigger in areas where the snowpack transitions from thick to thin or by a falling cornice
Evaluate terrain and avoid travelling below cornices
Confidence
Moderate
Avalanche Summary
Over the past 3 days explosives were used to drop cornices, some of these cornices triggered persistent slabs on the slopes below. The resulting avalanches were up to size 3 with crowns as deep as 3 meters.
On Tuesday several remote and naturally triggered cornice failures were reported. Some of these pulled slabs on the slopes below.
Snowpack Summary
By mid day on Thursday up to 10 cm of new snow could have accumulated with moderate southwest wind. This new snow will overlie a crust on all aspects and elevations, except for north facing terrain in the alpine, Where up to 30 cm overlies a crust from late March. Below these crusts, the upper snowpack is moist.
Several weak layers from early March, mid February and late January can be found in the mid and lower snowpack. These layers remain a concern where a thick crust isnât present above.
The base of the snowpack is generally faceted.
Weather Summary
Wednesday Night
Mostly cloudy with 0 to 3 cm of snow. 15 to 30 km/h west ridgetop wind. Treeline temperature -9 °C.
Thursday
Mix of sun and cloud with 0 to 3 cm of snow. 15 to 30 km/h northwest ridgetop wind. Treeline temperature -6 °C.
Friday
Sunny. 10 to 20 km/h northwest ridgetop wind . Treeline temperature -2 °C.
Saturday
Sunny. 20 to 40 km/h west ridgetop wind. Freezing level rising to 2300 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Keep in mind that human triggering may persist as natural avalanches taper off.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Avoid areas with a thin or variable snowpack.
Avalanche Problems
Persistent Slabs
Various weak layers from the past 3 months are a concern in shallow north facing terrain. Be especially leary of slopes that match this description and have a cornice above.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 2 - 3
Cornices
Cornices have failed naturally in the region. Give these hazards a wide berth.
Aspects: North, North East, East, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1.5 - 2.5