Avalanche Forecast
Regions: Purcells.
With no or minimal overnight freezing, warm temperatures, sunshine and light rain will continue to destabilize the snowpack on all aspects and all elevations. Thoughtful terrain choices and conservative decision-making are essential for safe travel in the backcountry.
Confidence
Moderate - We have a good understanding of the snowpack structure and confidence in the weather forecast Uncertainty is due to the fact that cornice falls are particularly difficult to forecast.
Weather Forecast
An upper ridge builds in from the west and moves across the province on Monday. This will be associated with drying and clearing conditions before the next storm system moving in for Wednesday.Â
SUNDAY NIGHT: Mainly cloudy with isolated flurries/showers. Trace of precipitation. 15-25 km/h southwesterly winds. Low alpine temperature +3 C with freezing level around 2300 m.
MONDAY: A mix of sun and cloud with isolated flurries/showers. 2-4 mm. 25-30 km/h southwesterly winds. High alpine temperature +2 C with freezing level around 2200 m.
TUESDAY: Sunny with cloudy periods. No precipitation. 15-25 km/h northeasterly winds. High alpine temperature -2 C with freezing level around 1800 m.
WEDNESDAY: Mostly cloudy with isolated flurries. 2-4 cm. 20-40 km/h southwesterly winds. High alpine temperature -2 C with freezing level around 1800 m.
Avalanche Summary
On Saturday, a natural wind slab avalanche size 2 was observed on a southeast slope in the alpine. A few small loose wet avalanches were also reported on solar and north aspects.
Snowpack Summary
Recent snow and moderate wind have formed small pockets of reactive windslab in the alpine. Refrozen crust on all aspects as high as 2300 m, softening in the afternoon at all elevations, and on steep, sunny slopes. Recent warm temperatures, sun, and rain have made the top 5-15 cm of the snowpack moist. At very low elevations, the snowpack may be wet and isothermal, depending on overnight freezing levels.Â
30 to 75 cm below the snow surface, you'll find a frozen sun crust on solar aspects. This layer was buried in early March, and it was a cause of several avalanches last week, but the recent warm weather seems to have helped this layer heal.Â
The lower snowpack is generally strong and well bonded.
Terrain and Travel
- Avoid steep slopes when air temperatures are warm, it is raining, or solar radiation is strong.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Avalanche Problems
Loose Wet
Wtih no overnight freezing forecasted, the surface snow will not refreeze except maybe at very high elevations. The more the snow feels like a slurpy, the more likely loose wet avalanches will become. Especially avoid steep slopes when they are baking in the sun.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 2
Cornices
Cornices are large at this time of the year and warm temperatures may cause them to become weak. Cornice failures are dangerous on their own, but also have the potential to trigger larger avalanches on the slopes below.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 2 - 3
Wind Slabs
Westerly winds have redistributed up to 10 cm of recent snow into small wind slabs on lee features in the alpine and treeline.
Use extra caution near ridgetops, especially when the slope underneath is steep and/or hard. Even a small avalanche can knock you off balance, so consider the consequences of a fast slide down a hard slope.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 2