Avalanche Forecast
Regions: Bull, Dogtooth, East Purcell, Purcells, West Purcell.
If a thick, hard surface crust is present, avalanche activity is unlikely.Buried weak layers continue to produce sporadic large avalanches on high-elevation northerly slopes.
Confidence
Moderate
Avalanche Summary
Friday, a deep persistent slab was triggered by sledders east of Wasa (see photo below).Several wind slabs up to size 2 also occurred in the Western Purcells on lee alpine slopes.
Thursday, a few large cornice failures were triggered with warming, along with a large (size 2.5) wind slab on a northwest alpine slope.
A large persistent slab (size 2.5) failed on a northeast alpine slope near Panorama. It was suspected to have occurred early in the week.
Snowpack Summary
Around 10 to 30 cm of snow accumulated this week, with the highest amounts in the Western Purcells. Lower elevations and slopes that face the sun generally have a thick surface crust that can soften and become moist or wet with daytime warming. Shady alpine slopes likely still have dry snow and some lingering wind slabs.
Several persistent weak layers of crusts and/or facets can be found in the mid and lower snowpack. These layers remain a concern where there is no thick and supportive crust above them.
The base of the snowpack is generally faceted.
Weather Summary
Saturday Night
Mostly clear. 30 to 40 km/h northwest ridgetop wind. Treeline temperature -8 °C. Freezing level 1600 m, falling to valley bottom.
Sunday
Sunny. 10 to 20 km/h west ridgetop wind. Treeline temperature 0 °C. Freezing level rising to 1900 m.
Monday
Sunny. 5 to 15 km/h variable ridgetop wind. Treeline temperature +3 °C. Freezing level rising to 2500 m.
Tuesday
A mix of sun and cloud. 15 to 35 km/h west ridgetop wind. Treeline temperature +2 °C. Freezing level rising to 2300 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avalanche activity is unlikely when a thick melt-freeze crust is present on the snow surface.
- Be aware of the potential for large avalanches due to buried weak layers.
- Wind slabs are isolated, but may remain reactive.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Avalanche Problems
Persistent Slabs
Several persistent weak layers exist in the mid to lower snowpack. Persistent slab avalanches remain possible to trigger on northerly upper-elevation slopes where there is no thick supportive crust on the surface.
Aspects: North, North East, North West.
Elevations: Alpine, Treeline.
Likelihood: Unlikely - Possible
Expected Size: 2 - 3.5
Wind Slabs
Lingering wind slabs may be triggered on leeward upper elevation slopes with no surface crust.
Aspects: North, North East, East, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 2
Loose Wet
Remain cautious on sun-exposed slopes during the warmest parts of the day, especially if the snow surface is moist or wet. Use appropriate sluff management techniques.
Aspects: South East, South, South West, West.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 1.5