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

Feb 5th, 2020–Feb 6th, 2020

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, human triggered possible.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

South Coast Inland.

The danger rating is based on the forecast snowfall amounts for the south of the region where 20-35 cm of snow are expected by Thursday evening. Be careful when transitioning into wind affected terrain. Fresh wind slabs will be sensitive to human triggering. 

Confidence

Low - Uncertainty is due to difficult to forecast freezing levels. Forecast precipitation (either snow or rain) amounts are uncertain.

Weather Forecast

Wednesday Night: Snow, flurries in the north of the region and accumulation 10-15 cm in the south, moderate to strong northwest wind, alpine high -5 C. Freezing level 1200 m.

Thursday: Snow, accumulation 5-10 cm in the north of the region and 10-20 cm in the south, moderate to strong northwest wind, alpine high -2 C, freezing level 800 m in the north of the region and 1500 m in the south.

Friday: Flurries, accumulation 5 cm in most parts of the region and 20 cm in the very south, moderate west wind, alpine high -4 C, freezing level 800 m in the north of the region and 1500 m in the south.

Saturday: Mix of sun and cloud, snow, accumulation up to 10 cm, moderate west wind, alpine high -4 C, freezing level 900 m.

Avalanche Summary

There have been no recent reports of avalanche activity. The deep persistent slab avalanche activity observed during last weekend's storm in the northern portion of the region seems to have tapered off. Although the likelihood of triggering has reduced there is is still concern for deep releases in that part of the region.

Snowpack Summary

New snow develops fresh wind slabs in the alpine and covers recent wind slabs. Extreme southwest wind during the storm last weekend has scoured windward aspects, formed deep loaded pockets in alpine lees and contributed to rapid cornice growth. Below 1800 m, snow overlies a crust and tapers with elevation.

In the north part of the region (ie. Goldbridge/Duffey/Hurley), a few deep instabilities exist in the snowpack, including a weak basal facet crust complex. This has been the failure plane in ongoing reports of very large, deep persistent avalanches.

The south of the region, including the Coquihalla and Manning areas, currently have no concerns about deeply buried weak layers.

Terrain and Travel

  • Watch for avalanche hazard to increase throughout the day.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
  • Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.