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Avalanche Forecast

Archived

Jan 24th, 2023–Jan 25th, 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.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely.

Regions

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

A mix of old and new wind slabs in exposed terrain means some may now be quite stubborn while others remain sensitive to human triggering.

Pair your wind slab avoidance with line choices where there is a thick, consistent snowpack and you'll be managing the problematic basal snowpack at the same time.

Confidence

Moderate

Avalanche Summary

Ski cutting in the Fernie area on Monday yielded numerous small (size 1) wind slab releases. This problem affects all aspects and the most recent slab formations will likely remain reactive to human triggering through Wednesday at least.

Sunday saw a cornice fail naturally but it did not trigger buried weak layers in this instance. Even so, it's a great reminder to be mindful and to practice avoidance of overhead hazards.

Although they have not produced avalanches in the last few days, a deep persistent slab problem still affects the region and should steer you away from thin or variable depth snowpack locations and shallow rocky start zones throughout the region.

Snowpack Summary

Surfaces in exposed areas are becoming heavily wind-affected above 1800 to 2000 m by winds from variable directions. Wind slabs have been continuously forming and gradually stabilizing on a range of aspects as a result of this pattern. Below this elevation, 10-20 cm of recent snow has settled on a melt-freeze crust that developed earlier this month.

A crust/facet layer, 2 to 15 cm thick at treeline is 50 to 90 cm below the surface. Where it's thickest, it caps the settled and consolidated mid-snowpack.

Another crust/facet layer is down 70 to 150 cm. Below this crust, the basal snowpack is weak and faceted. The total snowpack depth ranges between 120 and 250 cm.

Weather Summary

Tuesday night

Tues Night: Increasing cloud throughout night, nil precipitation, winds light from the Southwest, treeline temps around -5 C.

Wednesday

Cloudy in AM decreasing throughout day, trace precipitation, winds light from the Southwest, treeline temps around -4 C.

Thursday

A mix of sun and cloud, nil precipitation, winds light from the Southwest, treeline temps around -6 C.

Friday

Partly cloudy, trace precipitation, winds light and variable throughout day, treeline temps around -4 C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
  • In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Avoid exposure to slopes that have cornices overhead.

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.