Avalanche Forecast
Issued: Mar 17th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
shorton,
Avalanche Canada
Little change is expected due to a stable weather pattern. Be extra cautious as slopes warm up throughout the day.
Summary
Confidence
High - We have a good understanding of the snowpack structure and confidence in the weather forecast
Weather Forecast
A high pressure system brings clear dry conditions for the week.
TUESDAY NIGHT: Clear skies, light north wind, freezing level drops to valley bottom, alpine temperatures drop to -8 C.
WEDNESDAY: Mostly sunny, light northwest wind, freezing level climbs to 1700 m in the afternoon, alpine temperatures reach -2 C.
THURSDAY: Mix of sun and cloud, light southeast wind, freezing level climbs to 1400 m in the afternoon, alpine temperatures reach -4 C.
FRIDAY: Sunny, light to moderate northwest wind, freezing level climbing 1700 m in the afternoon, alpine temperatures reach -2 C.Â
Avalanche Summary
Recent avalanche activity has primarily been small (size 1-1.5) wet loose avalanches in steep south-facing terrain and a few wind slab avalanches in alpine terrain. Some of the wind slabs have been large (size 2.5-3), primarily on south and southeast facing slopes. Persistent slab avalanche activity has starting to quiet down. Over the past two weeks, only a few small to large (size 1-2) avalanches have released on the late February surface hoar layer. They have most often released between 1700 and 2100 m on northwest to east aspects.
Looking forward, daytime warming will create potential for loose avalanches on steep sun-exposed slopes and could increase the likelihood of wind and persistent slab avalanches.
Snowpack Summary
Surface conditions are highly variable with a mix of crusts, moist snow, and hard wind slabs. The surface will become moist on sun-exposed slopes and at lower elevations throughout the day. A few different layers of surface hoar and melt-freeze crust exist in the upper snowpack. This layers have produced some isolated avalanches over the past two weeks and remain possible to trigger. One layer was buried a week ago and may be found about 20 to 40 cm deep, but the most widespread layer was buried in late February and is now 40 to 80 cm deep. This layer is most commonly found in open trees (e.g. in this MIN). The remainder of the snowpack is strong and well-settled.
Terrain and Travel
- The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
- Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
Problems
Wind Slabs
Wind slab avalanches remain a concern. Watch for wind slabs in unusual terrain features after last week's strong wind from the northeast.
Aspects: North, South East, South, South West, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of surface hoar exists 40 to 80 cm below the surface and has produced a few large avalanches over the past few weeks. The problem seems most prevalent on northwest to northeast aspects between 1700 m and 2100 m. While the likelihood of triggering a persistent slab avalanche is dropping, there is still some uncertainty about where and for how long this problem will persist.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 18th, 2020 4:00PM
