Avalanche Forecast

Archived

Nov 24th, 2024–Nov 25th, 2024

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

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

Fresh snow has improved ski conditions in the Icefields, but lingering windslabs exist and there is significant uncertainty around the Oct crust.

It’s a good time to let the snowpack form and take a conservative approach to early-season fun.

Confidence

Moderate

Avalanche Summary

Several size 1 loose dry avalanches out of steep rocky terrain were reported Saturday as the sun poked out. One of these pulling a windslab resulting in a sz 1.5.

On Friday, Sunshine Ski Hill had several results failing on the October crust. A small hand charge triggered a size 2.5, a skier triggered a size 2, and a number of other results.

Please consider helping forecasters and your backcountry community by submitting your observations to the Mountain Information Network.

Snowpack Summary

Recent storm snow sits on old windslabs and a faceted midpack. There is a thin crust 20-30cm below the surface, as well as a notable 5-15 cm thick crust from October near the base of the snowpack, surrounded by facets above and below. There is a lot of uncertainty about this layer in regards to the triggerability and the distribution.

Snow depth at Treeline is approx. 70 cm tapering off rapidly below. Alpine ~80 cm with variability due to wind redistributing the snow

Weather Summary

Monday

Cloudy with sunny periods. High -8 °C with winds from the southwest 10 km/h. Freezing level at valley bottom.

Tuesday

Cloudy with sunny periods. Low -15 °C and a High -11 °C with winds from the west 15 km/h. Freezing level at valley bottom.

Terrain and Travel Advice

Be careful as you transition into wind-affected terrain.
Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.

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.