Avalanche Forecast
Regions: Dogtooth, East Purcell, Purcells.
Avoid thin and rocky start zones, weak layers in the mid and lower snowpack are showing reactivity to human triggers.
Confidence
Moderate
Avalanche Summary
Explosive control yesterday produced slab avalanches; one stepped down to the weak basal facets at the base of the snowpack.
A remotely triggered slab was reported on a NE facing slope at 2300m in a shallow rocky area, also failing on the basal facets.
Snowpack Summary
The recent 30 cm of storm snow has likely been redistributed into deeper deposits on north and east facing slopes at higher elevations. This sits over a rain crust that has been observed up to 1900 m near Golden and 2200 m near Invermere.
A concerning layer of surface hoar is now buried 40-70 cm deep. A widespread natural cycle may have destroyed this layer in steep features but it likely still lingers unaffected features.
The middle and base of the snowpack holds large, weak snow crystals. A hard crust may be found near the ground.
Treeline snowpack depths are variable and generally range between 60 and 100 cm. Snowpack tapers rapidly as you move lower in elevation.
Weather Summary
Sunday Night
Partly cloudy, trace amounts of snow. Southwest winds 10-20 km/h. Freezing levels drop back to valley bottom.
Monday
Mostly cloudy, no snowfall expected. Treeline temperatures around -7 °C. Light and variable wind.
Tuesday
Clearing skies with no snowfall expected. Southerly winds, 10-20 km/h. Treeline temperatures around -10 °C
Wednesday
Partly cloudy with no snowfall expected. Southerly winds increase, around 40 km/h. Treeline temperatures around -10 °C
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Make conservative terrain choices and avoid overhead hazard.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
- Stay off recently wind loaded slopes until they have had a chance to stabilize.
Avalanche Problems
Wind Slabs
Winds have built deeper and more reactive slabs in north and east facing terrain features. Slabs sit over a rain crust below ~2200 m. At higher elevations, slabs sit over recent storm snow - and may step down to buried weak layers.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2
Persistent Slabs
Surface hoar is most likely to be found at treeline elevations, and most triggerable where the rain crust disappears.
Weak facets sit at the base of the snowpack, recent avalanches have failed on or stepped down to this layer.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2.5