Avalanche Forecast
Issued: Nov 24th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
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Avalanche Canada
Incoming storm with heavy snow and wind will increase the avalanche hazard: expect a natural avalanche cycle Friday. Thursday will be more tricky as the storm snow accumulates and approaches a tipping point. Use increasing caution especially where the snow is wind affected.
Summary
Confidence
Weather Forecast
Wednesday Overnight: Weather system arriving overnight with 10 to 15 cm of snow and moderate to strong south west wind.
Thursday: Stormy day with warming temperatures raising freezing level to around 1200m. 15 to 25 cm of additional new snow. Continued moderate to strong south or southwest wind
Friday: By the end of the day it looks like another 15 to 25 cm bringing storm totals around 40 to 65 cm. Winds will start to ease and veer to the west as the storm ends. Temps will start to cool from the peak warming (when the freezing level rose to around 1500m).
Saturday: A brief cooler, drier, calmer day before the next system arrives.
Avalanche Summary
Get ready for a direct action avalanche cycle driven by lots of new snow and honking wind! With 65 cm of new snow by Friday, and possibly even more, falling in the alpine combined with strong south to west winds I expect size 2 storm slabs will be common on any aspect with the best candidates being slopes above 1200m and steeper than 30 to 35 degrees. Windslabs on lee and crossloaded slopes will be even more likely and bigger, up to size 3 is possible.
Remember, if you see slopes that have avalanched, similar slopes (same aspect, elevation, steepness, terrain feature) are prime candidates for something similar.
Snowpack Summary
The snowpack summary is available here.
Terrain and Travel
- Watch for rapidly changing conditions during periods of heavy loading from new snow, wind, or rain.
- As the storm slab problem gets trickier, the easy solution is to choose more conservative terrain.
- Expect slab conditions to change drastically as you move into wind exposed terrain.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
Problems
Storm Slabs
Incoming heavy weather means widespread storm slabs will develop at elevations above 1000m. Strong winds suggest reactive windslabs quickly developing on north through south east facing slopes in treeline and alpine terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Nov 25th, 2021 4:00PM
