Avalanche Forecast
Issued: Mar 18th, 2020 3:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
shorton,
Avalanche Canada
Avalanche danger is on a declining trend, however remain cautious of steep slopes at treeline elevations where buried surface hoar may exist.
Summary
Confidence
Weather Forecast
A high pressure system brings clear dry conditions for the foreseeable future.
WEDNESDAY NIGHT: Clear skies, light wind, freezing level drops to valley bottom, alpine temperatures drop to -8 C.
THURSDAY: Sunny with a few clouds, light wind, freezing level climbs to 1500 m in the afternoon, alpine temperatures reach -2 C.
FRIDAY: Sunny, light to moderate northwest wind, freezing level climbing 1500 m in the afternoon, alpine temperatures reach -2 C.
SATURDAY: Mix of sun and cloud, light west wind, freezing level climbing 1500 m in the afternoon, alpine temperatures reach -2 C.
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 on south and southeast slopes. Some large (size 2.5-3) wind slabs were reported over the weekend, but since then only small slabs (size 1) have been reported. 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 both loose and slab avalanches on steep sun-exposed slopes.
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. These 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
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
- Carefully evaluate steep lines for wind slabs.
Problems
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 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 19th, 2020 4:00PM
