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 5th, 2023–Dec 6th, 2023

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

Regions

Lizard-Flathead, Akamina, Flathead, Lizard.

Travel in avalanche terrain is not recommended as an intense storm loads a weak snowpack. The weather is triggering natural avalanches.

Confidence

High

Avalanche Summary

Many large (size 2) slab avalanches were observed in the region on Tuesday, being triggered by the heavy rain. This trend may continue into Wednesday as the storm continues.

Snowpack Summary

A warm storm is rapidly loading the snowpack with snow at high elevations and rain elsewhere, including a weak and feathery surface hoar layer buried about 20 to 30 cm deep. This weak layer may be associated with a hard melt-freeze crust.

The remainder of the snowpack is weak and faceted.

Snowpack depths are approximately 60 to 80 cm at treeline, which rapidly tapers with lower elevations.

Weather Summary

Tuesday Night

Cloudy with heavy rain or 20 to 40 cm of snow near the mountain tops above 2100 m. Southwest alpine wind 40 km/h. Treeline temperature 2 °C. Freezing level 2300 m.

Wednesday

Cloudy with heavy rain or 15 to 25 cm of snow near the mountain tops above 2000 m. Southwest alpine wind 40 km/h. Treeline temperature 1 °C. Freezing level 2100 m.

Thursday

Cloudy with 20 to 50 cm of snow. Southwest alpine wind 20 to 40 km/h. Treeline temperature -3 °C. Freezing level 1900 m dropping to 1300 m.

Friday

Mostly cloudy with 5 cm of snow. Southwest alpine wind 20 km/h. Treeline temperature -6 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Avoid avalanche terrain during periods of heavy rain.
  • Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
  • If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.
  • Early season avalanches at any elevation have the potential to be particularly dangerous due to obstacles that are exposed or just below the surface.

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.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.