Avalanche Forecast
Issued: Dec 25th, 2020 8:06AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
Percy Woods,
Persistent weak layers linger in the snowpack. Avalanches triggered on these layers may be large and of high consequence.
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Merry Christmas!
Summary
Weather Forecast
A mix of sun and cloud with no precipitation.
Alpine High -4 °C with light southerly winds.
Freezing level: 1300 metres.
Tonight through tomorrow flurries should bring us 10cm of storm snow with freezing level around 1000m.
Snowpack Summary
The recent storm dropped 120cm snow accompanied by warm temps and strong S-SW winds. Slab formation is widespread. Weak layers; Dec 13 surface hoar/facets are down 70-110cm, Dec 7 crust/surface hoar layer is down 110-130cm+. The Nov 5 crust lingers near the base of the snowpack and several avalanches over the storm period stepped down to it.
Avalanche Summary
Bagheera SE face size 3.5 overnight Wednesday. Two size 2-2.5 slabs SE slopes just west of Christmas Couloir, Ursus Major early Thursday. One skier accidental size 2 slab avalanche SE Couloir on Mt Afton mid day Thursday. Avalanche control by MOT produced two size 4 avalanches just west of the Glacier Park boundary on Wednesday.
Confidence
Problems
Wind Slabs
120cm of storm snow in the past week with mild temperatures and strong S/SW winds. Post storm strong N'ly winds reverse loaded S'ly aspects too, expect slab formation on all aspects in the alpine and exposed areas of TL.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
- Be wary of slopes that did not previously avalanche.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
The Dec 7th surface hoar/crust and Dec13th surface hoar layer continue to produce sporadic large slab avalanches. Wind slabs have lots of potential to step down to this layer.
- Be aware of the potential for wide propagations.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 26th, 2020 8:00AM
