Avalanche Forecast

Archived

Feb 16th, 2023–Feb 17th, 2023

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, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Lizard-Flathead, South Rockies, Flathead, Lizard, Bull, Elkford East, Elkford West.

Multiple generations of wind slab now exist in exposed alpine and treeline terrain so if you go looking for trouble, you can probably still find it. Avoid the problem and seek out better quality riding in sheltered terrain.

Confidence

High

Avalanche Summary

A wind slab avalanche was reported in this great MIN from Fish Bowl near Fernie on February 15th.

Other small wind slab and dry loose avalanches have been reported in the area over the last 48hrs.

Snowpack Summary

Small amounts of recent new snow has been redistributed by southwest winds into either wind slabs or wind pressed surfaces. In addition, a sun crust has formed on steep solar aspects all the way up to low alpine elevations. Given this, quality riding can still be found in sheltered terrain.

The middle of the snowpack is well consolidated and sits on a thick crust. The bottom of the snowpack still consists of weak, sugary crystals that are slowly gaining strength in areas with a deeper snowpack.

Cornices continue to grow with the wind.

Deep persistent slab avalanches should still be on your radar in areas outside of the Lizard Range such as the Bull River, Elkford, and the Flathead.

Weather Summary

Thursday night

Increasing cloudiness through the night. Flurries delivering 2-4 cm of snow. Wind from the southwest 20 km/h. Temperature -4˚C.

Friday

Mostly cloudy. 5 cm of new snow. Wind from the southwest at 15 km/h. Temperature -4˚C.

Saturday

Cloudy. 5 - 10 cm of new snow. Wind from the southwest 15 km/h in the morning becoming north at 10 km/h in the afternoon. Temperature -5˚C to -2˚C.

Sunday

A mix of sun and clouds as a short lived ridge sweeps through. Winds from the southwest at 10 km/h. Temperature -8˚C in the morning rising to -2˚C in the afternoon.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Wind slabs are most reactive during their formation.
Watch for areas of hard wind slab on alpine features.
Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.
Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.

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.