Avalanche Forecast
Issued: Dec 23rd, 2020 8:05AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
ross campbell,
Considerable avalanche hazard and sunny days after a big storm is traditionally the most common conditions for avalanche incidents!
Summary
Weather Forecast
Today: Sunny with cloudy periods as Rogers Pass is under a ridge of high-pressure. No precipitation, light SW winds, a inversions of temperatures is forecasted to start today.
Tonight: Clear with valley fog, inverted temperatures, light winds, and no precipitation.
Thursday: Sunny/high-pressure, light winds, and no precipitation.
Snowpack Summary
140cm of snow over the last 6 days, along with strong S-SW winds and warm temps, has created a sensitive slab at all elevations. The Dec 13 surface hoar/facets are down 140cm+ and the Dec 7 crust/surface hoar layer is down 150cm+. The Nov 5 crust lingers near the base of the snowpack and several avalanches over the storm period stepped down to it.
Avalanche Summary
On Monday evening artillery and RACS controlled avalanche to size 4, averaging size 3. Naturals observations yesterday, from Monday night's avalanche cycle up Connaught creek to size 3.5 in a MIN report. Natural activity has decreased with the passage of the storm, as we are now into a more benign weather pattern. Human triggering remains likely.
Confidence
Problems
Wind Slabs
~110cm of storm snow fell in the last week with mild temperatures and strong S/SW winds. Post storm strong Northerly winds reverse loaded southerly aspects too, so expect slab formation on all aspects especially in the alpine and exposed areas of TL.
- Keep an eye out for reverse loading created by N-NE winds.
- If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
The December 7th surface hoar/crust paired with the December 13th surface hoar has made an excellent weak layer for LARGE slab avalanches. Storm or wind slabs have lots of potential to step down to this layer.
- Be aware of the potential for wide propagations.
- Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 24th, 2020 8:00AM
