Avalanche Forecast

Archived

Feb 16th, 2023–Feb 17th, 2023

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 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

Tumbler.

Avoid wind-loaded features where new wind slabs are forming. Cornices continue to grow in the region, avoid exposure to large open slopes threatened by overhead hazards.

Confidence

Moderate

Avalanche Summary

No new avalanches reported in the area. Please continue to submit your observations to the MIN.

Looking forward, wind slabs formed by the recent snow and moderate winds are covering old wind slabs that are becoming stubborn but may still be triggered by large loads like a cornice or machine.

Snowpack Summary

Up to 30 cm of new snow (highest snowfall totals at Core Lodge) and wind will continue to build wind slabs in open terrain at treeline and alpine elevations. These new wind slabs are building over various surfaces of old wind slabs, soft snow in sheltered areas and a melt-freeze crust found below 1200 m.

The mid-pack is consolidated but variable in depth depending on aspect and elevation.

The lower snowpack is composed of large and weak facets formed in November and most likely triggerable in steep, rocky alpine terrain.

Weather Summary

Thursday night

Clearing overnight, 30 to 40 km/h southwest winds, treeline temperatures around -10 °C

Friday

Increasing clouds with isolated flurries beginning overnight, accumulation 3 to 5 cm, 30 to 40 km/h southwest winds, treeline temperatures -10 °C

Saturday

Mainly cloudy with isolated flurries, accumulation 2 to 5 cm, 40 to 50 km/h winds, treeline temperatures -10 °C.

Sunday

Mainly cloudy, isolated flurries with 2 to 3 cm accumulation, 40 to 50 km/h winds, treeline temperature -5 °C

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Don't let the desire for deep powder pull you into high consequence 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.