Avalanche Forecast

Archived

Dec 6th, 2024–Dec 7th, 2024

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

Kananaskis, Bow Valley, Highwood Pass, North 40, Spray - KLakes.

Snow is coming! Amounts are still up in the air, but we are optimistically hoping for 10-20cm by Sunday. The ratings for Saturday take the higher amounts into consideration, but expect hazard to rise with any new snow.

Confidence

Moderate

Avalanche Summary

Despite being warm and windy, the loose wet activity has stopped. Nothing new from today.

Snowpack Summary

Extended warm weather has done a number on our snowpack. Lots of wind scouring out there, with moderate wind loading in lee terrain. We can expect a widespread crust to form tonight, and likely stay as snow arrives tomorrow. The character of the interface will be the thing to watch as there are a few variables at play. Re-freeze timing, snow amounts and aspect distribution will all play parts in how this crust/interface develops. Aside from new crust speculation, the deeper layers are still lingering below but they are becoming less and less apparent as a crust and more apparent as a weak layer made up of depth hoar and facets.

Weather Summary

Temperatures will cool slightly tonight and settle at -8°. Daytime high is only a degree or two warmer. Snow forecasts don't quite agree on expected amounts for tomorrow, but hey, atleast there's snow in the forecast! Expect anywhere from 10-20cm by tomorrow evening. Ridge winds will average 40km/hr from the west for most of the day.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid steep terrain that is rocky and thin.
Pay attention to isolated wind affected features in the alpine, as well as cross-loaded features at treeline.
Avoid freshly wind-loaded terrain features.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.