Avalanche Forecast
Issued: Apr 7th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
wlewis,
Avalanche Canada
Watch for fresh and reactive wind slabs where new snow is available for transport.
Keep an eye on snow conditions as the sun may break out on Saturday, rapidly moistening the snow and increasing reactivity.
Summary
Confidence
Avalanche Summary
Warmer temperatures and some sun effect on Thursday produced small wet loose avalanches.
Wind slabs were last reported earlier in the week, in north-facing terrain features. New snow and wind continue to provide the potential for developing fresh and reactive wind slabs.
On Saturday a rider triggered a cornice fall from a distance, which produced a size 3 persistent slab avalanche on a northeast aspect at 1750 m. The avalanche was 200 cm deep and was suspected of having failed on a layer of facets above a crust buried in January.
Snowpack Summary
Around 25 cm of recent snowfall will continue to be redistributed by southerly winds into wind slabs over previously wind-affected snow on north and east facing slopes. South facing terrain will likely be stripped back to a crust by these winds. Lower elevations likely have a crust on or near the surface from recent warm temperatures.
A weak layer of surface hoar/crust/facets buried in early January is now buried over 1 m deep in most areas. This layer has produced recent avalanche activity and remains a concern in terrain where the snowpack is thin. The lower snowpack consists of basal facets, particularly in shallow areas.
Our field team travelled far and wide on Thursday, check our their MIN report here for current conditions.
Weather Summary
Friday Night
Mostly cloudy with up to 5 cm of snowfall. Moderate southerly winds. Freezing levels drop to valley bottom.
Saturday
Mostly cloudy with 5 cm of snow with strong southerly winds. Freezing levels around 1000 m.
Sunday
Cloudy with light snowfall with strong southerly winds. Freezing levels around 1000 m.
Monday
A mix of sun and cloud with moderate southwest winds. Freezing levels remain low around 500 m. Flurries are possible in isolated areas.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Carefully evaluate steep lines for wind slabs.
- Use caution on large alpine slopes, especially around thin areas that may propagate to deeper instabilities.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Wind Slabs
Wind slabs are present at higher elevations, in north and east facing terrain features. Small accumulations of fresh snow and continued winds may continue to build these slabs.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A layer of facets sitting on a crust buried in January has recently been reactive. Triggering is most likely in areas where the snowpack is thin and weak, or with a heavy load like a cornice fall or the weight of a smaller avalanche in motion triggering this deeper layer.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 8th, 2023 4:00PM
