Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Dec 31st, 2022–Jan 1st, 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 possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

Sea To Sky, Brandywine, Garibaldi, Homathko, Powell River, Spearhead, Tantalus, Sasquatch, Sky Pilot, Tetrahedron.

Happy New Year! Have a safe start to this new year by avoiding wind-loaded areas and practicing good travel habits. Recently formed wind slabs overlie a slick crust and are expected to remain reactive to human triggering.

A low-probability but high-consequence deep persistent slab problem should have you avoiding thin rocky areas and exposure to overhead hazards. Learn more about how to manage this problem in the avalanche summary...

Confidence

Moderate

Avalanche Summary

On Friday, numerous natural and human-triggered storm slabs were reported up to size 2. These slabs mainly occurred in wind-loaded terrain and failed on the underlying rain crust.

Several large (size 2 to 2.5) slab avalanches were produced during explosive control work on Thursday. All in alpine terrain on a variety of aspects. A number of avalanches slid on deep persistent weak layers, with crowns of 1.5 to 2 m deep.

The weak facet/crust interface near the base of the snowpack has begun to show reactivity to large loads in the past week. This layer now presents a low-probability but high-consequence problem that is atypical for our coastal snowpack. Learn more about the nature of this deep persistent slab problem from this forecaster blog.

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

Snowpack Summary

This week, 20-60 cm of storm snow was accompanied by strong southwest winds, creating hard wind-affected surfaces in open areas and wind slabs in lee terrain features. This new snow overlies a rain crust formed earlier in the week. This crust is thin at higher elevations and up 2 cm thick below treeline.

The mid-snowpack consists of moist snow at lower elevations and a series of crusts and denser snow at upper elevations.

Near the base of the snowpack, a weak facet/crust layer can be found.

Total snow depths are roughly 100 to 200 cm at treeline.

Weather Summary

Saturday night

Clear periods. Alpine temperatures drop to a low of -6 °C. Mostly light southwesterly ridge wind occasionally gusting to 30 km/h. Freezing level at valley bottom.

Sunday

A mix of sun and cloud. Alpine temperatures reach a high of -3 °C. Ridge wind light to 20 km/h from the southwest. Freezing level rises to 700 metres.

Monday

A mix of sun and cloud. Alpine temperatures reach a high of -2 °C. Mostly light southerly ridge wind occasionally gusting to 40 km/h. Freezing level rises to 900 metres.

Tuesday

Cloudy with sunny periods and isolated flurries. Alpine temperatures reach a high of -4 °C. 20km/h gusting to 50 km/h southerly winds at ridgetop. Freezing level rises to 800 metres.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
  • Keep in mind the crust offers an excellent bed surface for avalanches.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.

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.