Avalanche Forecast

Archived

Dec 27th, 2022–Dec 28th, 2022

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 possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

South Coast Inland, Birkenhead, Duffey, South Chilcotin, Stein, Taseko.

Use caution as you transition into wind-affected areas, especially around ridge crests, rollovers, and in steep terrain.

Deeper weak layers remain a concern for step-down avalanches in wind-loaded terrain.

Confidence

Moderate

Avalanche Summary

On Monday, evidence of a natural avalanche cycle, both wet slab and wet loose avalanches, was observed on all aspects at all elevations. Avalanches were up to size 3 and likely occurred during the rain event Sunday night.

Please continue to post your observations and photos to the Mountain Information Network.

Snowpack Summary

30 - 40 cm of storm snow has fallen since December 22. New snow has been redistributed by strong southerly winds into deep pockets in the alpine. This weekend's warm temperatures and rain have impacted lower elevations, a melt-freeze crust has formed below 1600 m. The new snow covered a layer of weak and unconsolidated snow produced by the recent cold weather.

The winter snowpack is not as deep as usual, and along with a cold and dry early winter, the lower snowpack consists of weak, unconsolidated facets and depth hoar crystals. Snowpack depths average 50-200 cm at treeline.

Weather Summary

Tuesday Night

Mainly cloudy. Precipitation continues tonight with another 10-15 mm. Variable 25 km/h winds. Ridgetop low temperature -7. Freezing levels valley bottom.

Wednesday

Isolated flurries, 2-5 mm. Southwesterly winds 20 km/h. Ridgetop high temperature -8. Freezing levels valley bottom.

Thursday

Cloudy with sunny periods and isolated flurries, 2-5 mm. Southerly winds 20 km/h. Ridgetop high temperature -4. Freezing levels hover from 500 -1000m.

Friday

Cloudy with flurries, 5-10 mm. Westerley 20 km/h winds. Ridgetop high temperature -4. Freezing levels hover near 800 - 1300 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be especially cautious as you transition into wind affected terrain.
Stay off recently wind loaded slopes until they have had a chance to stabilize.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

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.