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 23rd, 2021–Dec 24th, 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, 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.

Regions

North Columbia.

Give the snowpack time to strengthen before pushing into bigger terrain. Expect deeper and more reactive deposits in wind loaded features as you move to higher elevations. Sheltered slopes with minimal wind effect will offer the best conditions.

Confidence

Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.

Weather Forecast

The trough exits the region, leaving flurries in its wake. Arctic air begins to push South into the interior, steadily dropping temperatures. Expect a daily refresh of low density snow through to Boxing Day.

THURSDAY NIGHT: Light snowfall brings up to 5cm overnight with moderate southwest winds.

FRIDAY: Cloudy skies with flurries over the day, up to 5cm. Winds remain moderate from the southwest. Alpine high of -10.

SATURDAY: Cloudy with light snowfall, 2-5cm over the day and another 5-10cm overnight. Moderate to strong south-easterlies. Alpine high of -15. 

SUNDAY: Snowfall tapers over the day delivering light accumulations with moderate easterly winds. Alpine highs of -20.

Avalanche Summary

Naturally triggered slab avalanches to size 1.5 were observed on all aspects yesterday at treeline and above with the addition of heavy snowfall and wind. Several human triggered slabs up to 40cm deep were also reported. 

If you go out in the mountains, please submit your findings and photos through a Mountain Information Network report.

Snowpack Summary

Up to 30cm of new snow has fallen this week. Recent strong southwest winds have created deeper slabs in wind loaded features at treeline and above. 

Prior to this storm, a weak layer of surface hoar formed. These grains are expected to have been preserved on sheltered slopes at treeline and below. Expect increased reactivity of the storm snow in these areas. 

The most significant feature in the snowpack is a widespread thick crust that formed in early December. It currently sits 100-150cm below the surface and exists up to 2200m in the North Columbia's. In some places, overlying snow is well-bonded to the crust, but in others, weak faceted grains have been observed above it. The facets above the crust are most prominent at treeline where the crust is thinner. In areas where the crust is buried deeper than one meter, it has begun to decompose and show variable reactivity.

Terrain and Travel

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.

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.