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 6th, 2021–Dec 7th, 2021

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

Regions

Sea To Sky.

Expect to see slab formation in recent snow due to increases in wind and temperature over the day Tuesday. Watch for signs of instability like shooting cracks or recent avalanches.

Confidence

Low - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

At a glance, we'll see a modest warm up on Tuesday, new snow arriving with strong wind overnight, then cooling down on Wednesday.

Monday night: Cloudy. Light southwest wind. Freezing level 500 m.

Tuesday: Flurries starting in the afternoon, accumulating up to 5 cm. Light to moderate southwest wind. Treeline high temperatures around -1. Freezing level rising to 1000 m.

Wednesday: Overnight snow 10-20 cm. Strong southwest wind. Treeline high temperatures around -7. Freezing level 500 m.

Thursday: Mostly cloudy. Light to moderate southwest wind. Treeline high temperatures around -7. Freezing level 500 m.

Avalanche Summary

On Monday, small loose dry and soft slab avalanches were observed naturally up to size 1 and up to size 1.5 with skier and explosive loads.

On Sunday, a skier accidentally triggered a size 1 wind slab near a convex northeast aspect in the Whistler sidecountry. A few small solar triggered point releases were also observed on steep south aspects.

On Saturday, some loose dry sluffing and thin soft slab reactivity were observed in steep terrain and near ridge crests. The slide in this excellent MIN from Garibaldi Park appears to have initiated out of extreme terrain, breaking up quickly and entraining low density surface snow.

Snowpack Summary

Tuesday's mild temperatures will promote settlement in the 10-15 cm of recent snow sitting over a layer of surface hoar crystals. This recent snow may be lightly wind affected near ridge crest in the alpine. Below 1700 m, the recent snow sits over a thick, supportive crust. Above this elevation up to about 2100 m, this crust still exists, shallowly buried by older, wind-pressed snow. Faceting has been observed on the underside of the crust with a moist midpack below.

Average snow depths at treeline are now likely closer to 150-200 cm, with a whopping 450+ cm above 1900 metres. Snowpack depths taper dramatically to below threshold very near the treeline/below treeline boundary.

Terrain and Travel

  • Be alert to conditions that change with elevation.
  • Wind slabs may be poorly bonded to the underlying crust.
  • Keep in mind the crust offers an excellent bed surface for avalanches.
  • Even a small avalanche can be harmful if it pushes you into an obstacle or a terrain trap.

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.