Avalanche Forecast

Archived

Dec 23rd, 2022–Dec 26th, 2022

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 possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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

If heading out for a Holiday ski, climb or snowshoe, please remember that our current snowpack is extremely delicate and in a transitional state. We are on the upper and of the Considerable rating, and may even touch on High if the weather doesn't exactly match the forecast. Have a Happy and safe Holiday!

Confidence

Moderate

Avalanche Summary

A sz2.5 natural avalanche was noted today on what we call "Little Tent Ridge". It began in the south path, just below the radio repeater and ended up in the approach gully for Tryste Lake. It appears as though it entrained the entire snowpack.

Snowpack Summary

Wind transport is the name of the game right now. We've already seen evidence of an almost immediate avalanche cycle as wind slabs build. Expect this slab development to continue as wind directions drift from SW to W in the hours/days to come. The critical piece to remember is how even a small slab will entrain the loose snow and quickly cause avalanches to run far and fast. We may not have a deep snowpack, but if it all becomes involved in an avalanche, it will still be a big one!

Weather Summary

Lets hope Santa and Rudolph don't get blown straight to Saskatchewan tonight! Strong and gusty alpine winds will be ongoing for the next couple of days. For the moment it appears the really strong winds will be well above peak height with treeline winds in the light to moderate range. We are also expecting 4-8 cm of snow tonight as the weather change sorts itself out. A daytime high of -8 is expected for Christmas Day.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Be especially cautious as you transition into wind affected terrain.
Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.

Problems

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.

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.

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.