Avalanche Forecast

Issued: Dec 28th, 2019 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low.

Avalanche Canada shorton, Avalanche Canada

Triggering large avalanches is now a low probability/high consequence scenario that can be managed by careful terrain selection.

Summary

Confidence

Moderate -

Weather Forecast

SATURDAY NIGHT: Mainly cloudy, light wind from the northwest, alpine temperatures drop to -12 C.

SUNDAY: Cloudy with light flurries and 2-5 cm of snow, light wind from the north, alpine high temperatures around -8 C.

MONDAY: Mix of sun and cloud, light wind, alpine high temperatures around -8 C.

TUESDAY: Mostly cloudy, 30-50 km/h wind from the southwest, alpine high temperatures around -6 C.

Avalanche Summary

A few small (size 1) human triggered wind slab avalanches have been reported since Christmas Day. Last weekend a widespread cycle of very large deep persistent slab avalanches occurred (up to size 3.5), and more large avalanches were triggered with explosives the following days. The likelihood of triggering a deep persistent slab avalanche has declined since then, but the consequences are severe.

Snowpack Summary

Sheltered terrain has 10-30 cm of light powder while firmer wind slabs have formed at higher elevations. The loose snow overlies a hard rain crust below 1700 m. Hard snow in the middle of the snowpack sits above weak snow and decomposing crust layers near the bottom of the snowpack (80-150 cm deep). This weak snowpack structure resulted in very large avalanches last weekend. The likelihood of triggering a deep persistent slab avalanche has declined since then, but could still be possible from thin spots in steep terrain that did not avalanche in the last storm. Another round of avalanche activity on these deep weak layers is possible with the next significant storm.

Terrain and Travel

  • Avalanche hazard may have improved, but be mindful that deep instabilities are still present.
  • Avoid convexities, steep unsupported terrain and rocky outcroppings.
  • Use ridges or ribs to avoid areas of wind loaded snow.
  • Don't let the desire for deep powder pull you into high consequence terrain.

Valid until: Dec 29th, 2019 4:00PM