Avalanche Forecast
Issued: Mar 18th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Loose Wet and Deep Persistent Slabs.
mconlan,
Avalanche Canada
Assess for wind slabs in steep terrain. The sun will weaken the snow and cornices as the day progresses.
Summary
Confidence
Weather Forecast
WEDNESDAY NIGHT: Partly cloudy, light southeast wind, alpine temperature -6 C, freezing level 1000 m.
THURSDAY: Clear skies, light southeast wind, apine temperature -6 C, freezing level 1000 m.
FRIDAY: Clear skies, light to moderate northwest wind, alpine temperature -3 C, freezing level 1200 m.
SATURDAY: Mix of sun and cloud with isolated flurries, light to moderate north wind, alpine temperature -7 C, freezing level 900 m.
Avalanche Summary
No new avalanches were observed on Tuesday. Loose wet avalanche activity was observed on sun-exposed slopes on Monday.
Looking forward, avalanche activity may increase with daytime warming, as loose wet avalanche activity and cornice falls may occur naturally during the heat of the day. Lingering wind slabs and buried weak layers are still possible to be triggered by riders.
If you decide to travel in the backcountry, consider sharing your observations with us and fellow recreationists via the Mountain Information Network (MIN) to supplement our data stream as operators are shutting down. Even just a photo of what the day looked like would be helpful.
Snowpack Summary
Wind has varied in direction, meaning that wind slabs may be found on all aspects, particularly in steep terrain adjacent to ridges.
A weak layer of surface hoar crystals buried early March may be found around 40 cm deep. This layer has been most sensitive to human triggering at treeline elevations.
An early-season layer of faceted grains and melt-freeze crust near the base of the snowpack may linger. The most suspect locations to trigger this layer would be where the snowpack is thin near rocky outcrops. A large load, such as a cornice fall, also has the potential of triggering it.
Terrain and Travel
- Carefully evaluate steep lines for wind slabs.
- Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
- Avoid steep slopes when air temperatures are warm, or solar radiation is strong.
- Be aware of the potential for large avalanches due to the presence of buried surface hoar.
- Be aware of the potential for large avalanches due to the presence of a deep persistent slab.
Problems
Wind Slabs
Strong winds have drifted recent snow into wind slabs that are possible to trigger, especially where the slabs overly a weak layer of surface hoar.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
Loose wet avalanche activity is most likely during the heat of the day when clear skies prevail. Avoid overhead exposure on sun-exposed slopes as the snowpack heats up. Note that cornices are also large and could release during daytime heating.
Aspects: South East, South, South West.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
As spring-like weather takes over, the likelihood of avalanches releasing on faceted grains near the base of the snowpack increases. Sporadic destructive avalanches have occurred on these basal faceted grains, predominantly on north through east aspects in alpine terrain. Cornice falls are a possible trigger for deep persistent slab avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 19th, 2020 5:00PM
