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 12th, 2023–Feb 13th, 2023

Alpine
Natural and human triggered avalanches likely.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches possible, human triggered probable.
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 possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.

Regions

Northwest Coastal, Kitimat, Nass, Rupert, Seven Sisters, Shames, Stewart, Howson, Ningunsaw.

Continue to make conservative terrain choices. Storm slabs will likely still be reactive to rider traffic.

Confidence

Moderate

Avalanche Summary

We suspect that a large natural avalanche cycle has taken place during the day on Sunday.

On Wednesday, skiers triggered a large, size 2, avalanche near Ningunsaw. The Deep Persistent avalanche was triggered on an east aspect near ridgetop in a thin, rocky start zone and failed on basal facets.

Snowpack Summary

Up to 100cm of storm snow overlies older wind-affected surfaces and a supportive melt-freeze crust up to 1800 m and steep solar slopes. South-southwesterly winds have been scouring and pressing southerly slopes and wind slabs on northerly aspects. Large cornices are also being reported on many northerly aspects.

100 to 200cm of storm snow from the past two weeks is settling over a layer of facets, crust, and previous wind-affected surfaces in alpine terrain. We're continuing to track this layer given recent avalanches on this interface under the patterns of continuous loading and successive natural avalanche cycles.

The mid and lower snowpack continues to bond and stabilize while a number of buried weak layers are still being tracked by professionals in the region, having produced a few large avalanches in the not-too-distant past.

Weather Summary

Sunday Night

Stormy with 10 to 30cm of new snow expected. Moderate southwest winds and a low of -4 at 1500m.

Monday

Cloudy with up to 5cm of new snow expected. Light to moderate northwest winds and temperatures at 1500m falling throughout the day to -11.

Tuesday

A mix of sun and cloud with flurries in the afternoon bringing a few centimeters of new snow. Light southwest winds and a high of -8 at 1500m.

Wednesday

Cloudy with up to 10cm of new snow expected. Moderate southwest winds and a high of -6 at 1500m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Avoid exposure to slopes that have cornices overhead.

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.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.