Avalanche Forecast
Regions: Northwest Coastal.
In the south of the region, another 15-30 cm snow will fall by the end of the day Friday and continue to build reactive storm slabs. Moderate to strong south and west wind will form fresh wind slabs in lee terrain features in the alpine and at treeline.
Confidence
Moderate - Uncertainty is due to the track & intensity of the incoming weather system.
Weather Forecast
Thursday night: Cloudy, 15-25 cm snow in the southern half of the region, moderate to strong south wind, alpine low -2 °C, freezing level at 1000 m.
Friday: Mix of sun and cloud, 5-10 cm snow, moderate to strong west wind, alpine high -3 °C, freezing level at 1000 m.
Saturday: Mix of sun and cloud, up to 5 cm snow, moderate westerly wind, alpine high -6 °C, freezing level at 700 m.
Sunday: Sunny, trace of new snow, light to moderate northeast wind, alpine high -3 °C, freezing level at 1000 m.
Avalanche Summary
A few large wind slabs up to size 3 as well as several storm slabs to size 2 were triggered with explosives on Wednesday. Several small natural dry loose avalanches were reported, as well as a large (size 2.5) cornice failure. Skiers triggered several small wind slab avalanches in the alpine.Â
Many small dry loose avalanches were reported on Tuesday. A cornice failed naturally and entrained snow on the slope below, resulting in a size 2.5 avalanche.
Intense wind loading triggered some very large (up to size 3.5) wind slabs in the Bear Pass area that were reported on Monday morning.
Snowpack Summary
20-40 cm new snow add to 30-60 cm recent snow, which overlies a hard melt-freeze crust. The previous snow surface was wind affected and in some wind-exposed areas the wind had scoured the snow down to the crust.Â
Around 100 cm down, a layer of weak snow (facets or surface hoar) has been occasionally reported in sheltered areas. The distribution of this layer has been reported as isolated and is likely not a problem in many areas.
Cornices are very large and exposure to them should be minimized, especially during warm or windy weather.
Terrain and Travel
- Watch for fresh storm slabs building throughout the day.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Keep in mind the crust offers an excellent bed surface for avalanches.
- Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
- Even brief periods of direct sun could produce natural avalanches.
Avalanche Problems
Storm Slabs
In the south of the region, the current storm will add another 15-30 cm by the end of the day Friday to the 20-40 cm that fell on Thursday. Moderate to strong south and west wind will accompany the snowfall. Storm and wind slabs will continue to build and will be reactive to human triggers.
At lower elevations, the precipitation might fall as rain and weaken the snowpack resulting in wet loose avalanches.
If the sun comes out, the potential for wet loose avalanches will increase, especially on steep sun-exposed slopes.
The northern part of the region will likely see 5-10 cm of snow. The moderate to strong south and west wind will form fresh wind slabs in lee terrain features in the alpine and at treeline. Use ridges or ribs to avoid areas of wind-loaded snow.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1 - 2.5
Cornices
New snow and wind will add additional load to the already large cornices and might lead to cornice failures. Minimize overhead hazard and give cornices a wide berth when travelling on ridgetops.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 2 - 3.5