Avalanche Forecast
Issued: Mar 18th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
wlewis,
Avalanche Canada
Buried surface hoar continues to be reactive, especially in wind loaded features.
Stick to conservative terrain free from overhead hazard, and watch for signs of instability.
Summary
Confidence
Avalanche Summary
Recent storm snow remains reactive to human triggers, primarily failing on the buried surface hoar layer at treeline and in wind affected features. Numerous natural and rider accidental slab avalanches have been reported to size 2, including several remotely triggered slabs.
Explosive control work produced size 2.5 avalanches on the surface hoar/melt freeze crust interface.
Loose wet avalanches were reported to size 2 from low elevations as freezing level rose, and on south facing slopes due to sun affect.
Snowpack Summary
Southwest winds have created reactive deposits of wind slab on north to east facing terrain features near ridges. A melt freeze crust or moist snow exists on the surface at low elevations and on sun affected slopes into treeline elevations.
Up to 50 cm overlies large surface hoar crystals in terrain sheltered from the wind and sun, wind-affected snow in wind exposed terrain, and a hard melt-freeze crust on sun-affected slopes.
Another layer of surface hoar and/or weak faceted grains may be found about 60 cm deep, particularly on shaded aspects near treeline.
The remainder of the snowpack is consolidated and strong.
Weather Summary
Saturday Night
Increasing cloud with moderate to strong southerly winds. Freezing levels vary - mostly dropping below 1000 m.
Sunday
Cloudy with snowfall beginning early morning, 5 cm over the day and another 5 cm possible overnight. Strong southeast winds. Freezing levels reach 1200 m. Alpine high temperature of -6 °C.
Monday
Cloudy with moderate southeasterly winds. Light snowfall continues with another 5 cm possible. Freezing levels remain around 1000 m. Alpine high temperature around -7 °C.
Tuesday
Cloudy with moderate southeasterly winds. Freezing levels remain 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.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Minimize exposure to sun-exposed slopes when the solar radiation is strong.
Problems
Wind Slabs
Storm snow has been redistributed by southwest winds into deeper deposits, primarily found on north and east facing terrain features.
A buried layer of surface hoar is increasing reactivity and propagation. Avoid sheltered and shaded slopes where surface hoar is more likely to be found. On other aspects this layer is present as a melt freeze crust which has also produced avalanche activity.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 19th, 2023 4:00PM
