Avalanche Forecast
Issued: Apr 6th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Loose Wet.
wlewis,
Avalanche Canada
Wind slabs remain the primary concern. Watch for wind slabs around ridgelines and in mid slope terrain features in areas that see stronger winds.
Reactivity may increase on south facing slopes, even with brief periods of sunshine.
Summary
Confidence
Avalanche Summary
Reactive wind slabs were reported on Sunday at alpine elevations in north facing terrain.
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 to have failed on a layer of facets above a crust buried in January.
Snowpack Summary
Up to 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 the surface from recent warm temperatures.
A weak layer of surface hoar/crust/facets buried in early January is now 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.
Weather Summary
Thursday Night
Cloudy with 5-10 cm of new snow. Moderate to strong southerly winds. Freezing levels drop to valley bottom.
Friday
Mostly cloudy with up to 5 cm of snowfall. Moderate southerly winds. Freezing levels remain below 1000 m.
Saturday
5 cm of snow with strong to extreme southerly winds. Freezing levels around 1000 m.
Sunday
Light snowfall with strong southerly winds. Freezing levels around 1000 m.
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
Loose Wet
Periods of sunshine and rising temperatures over the day have the potential to create ideal conditions for wet loose avalanches in the recent storm snow. Watch for surface snow becoming moist or wet, and back of sun affected slopes..
Aspects: South East, South, South West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Apr 7th, 2023 4:00PM
