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 3rd, 2021–Dec 4th, 2021

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 unlikely, human triggered possible.
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

Northwest Coastal.

Remain cautious with terrain choices as the snow settles from an epic series of storms. Wind loaded features are the most likely to produce large avalanches.

Confidence

Moderate - We are confident about the possible sizes of avalanches, should one release; what is less certain is the likelihood of triggering.

Weather Forecast

Stormy weather lingers for one more night. Freezing levels remain mostly at valley bottom.

Friday Night: Mostly overcast. 5-15 cm new snow. Strong southwest wind. Alpine temperature around -13 C. Freezing level up to 250m.

Saturday: Partly Cloudy. Possible trace of new snow. Moderate northwest wind. Alpine temperature around -15 C.

Sunday: Mostly cloudy by the afternoon. No new snow expected. Moderate northwest wind. Alpine temperature around -15 C.

Monday: Clear morning, cloudy afternoon. No new snow expected. Moderate southwest wind. Alpine temperature above -10 C with possible temperature inversion

Avalanche Summary

The few avalanches reported on Thursday in the south of the region seemed to only move the recent storm snow.

 

On Wednesday morning, a few small natural avalanches were observed and explosive and machine control work produced size 1-2 storm slab avalanches.

Near Stewart, there is evidence that a widespread avalanche cycle occurred during the past storm, up to size 3 in wind loaded terrain at treeline and in the alpine. 

Snowpack Summary

30-60 cm of snow in the last 48 hours continues to be redistributed and built into slabs by moderate to strong winds. 

The previous wet storm produced a new crust that was buried Nov 30 or Dec 1. This crust exists up to 2000 m in the southwest of the region, and may only be found up to 1200 m in areas east of Terrace. Expect slab avalanches to propagate more easily on this crust and run far.

At higher elevations where this crust is not present, the storm snow overlies old wind slab or wind stripped ridge tops.

Treeline snowpack depths are estimated to be around 2-3 m, and a prominent crust can be found near the base of the snowpack.

Terrain and Travel

  • Be alert to conditions that change with elevation and wind exposure.
  • Avoid lee and cross-loaded slopes at and above treeline.
  • Keep in mind the crust offers an excellent bed surface for avalanches.

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.