Avalanche Forecast

Archived

Dec 26th, 2024–Dec 28th, 2024

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Jasper, Brazeau, Churchill, Cirrus-Wilson, Fryatt, Icefields, Maligne, Marmot, Miette Lake, Pyramid.

Happy Holiday's everyone.

Extreme winds over Christmas have scoured many slopes to ground and loaded others. Expect to find wind slabs!

Confidence

Moderate

Avalanche Summary

There was one size 2 wind slab, one gully south of the Ice climb "Schism Game" on Nigel Peak observed on the 25th.

Outside the park there have been recent reports of explosive results on the early season crusts producing avalanches up to size 2.5

There was a natural size 3 avalanche reported on the Grand Daddy Couloir on Bow Peak, in Banff National Park on December 24th.

Snowpack Summary

Strong to extreme winds have redistributed surface snow and scoured windward aspects. Sheltered locations may still hold 15cm of soft snow if winds did not get to it. In protected areas, a weak layer of 7mm Surface Hoar may be 10-30cm down. The mid pack is mostly made up of facets. At the bottom of the snowpack there are multiple early season crusts with facets above and below.

Weather Summary

Friday

Cloudy with sunny periods and isolated flurries.

Precipitation: Trace.

Alpine temperature: High -8 °C.

Ridge wind west: 15-30 km/h.

Saturday

Mainly cloudy with scattered flurries.

Accumulation: 4 cm.

Alpine temperature: Low -11 °C, High -7 °C.

Ridge wind southwest: 15-30 km/h.

Sunday

Cloudy with sunny periods and isolated flurries.

Precipitation: Trace.

Alpine temperature: Low -13 °C, High -7 °C.

Ridge wind southwest: 10-25 km/h.

Terrain and Travel Advice

Be careful as you transition into wind-affected terrain.

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.

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.