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 4th, 2020–Dec 5th, 2020

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

Regions

Cariboos.

The return of above freezing temperatures in the alpine may renew loose wet avalanche activity on steep sun exposed slopes.

Temperatures will be warmest in the northeast part of the region. If you're going out there, check out the forecast for the North Rockies.

Confidence

Low - Uncertainty is due to the limited number of field observations. Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack. Uncertainty is due to difficult to forecast freezing levels.

Weather Forecast

Friday night: Clear, moderate southwest wind, strong temperature inversion with above freezing air 1800-3200 m.

Saturday: Sunny, moderate southwest wind, strong temperature inversion with above freezing air 1800-3200 m.

Sunday: Sun and cloud, light to moderate southwest wind, freezing level 1100 m.

Monday: 5-10 cm new snow, light to moderate southwest wind, freezing level 1300 m.

Avalanche Summary

Loose wet avalanches size 1-2 likely occurred during the initial warmup on Wednesday, and to a lesser extent on Thursday and Friday.

Our eyes and ears in the mountains are limited this winter due to fewer professional observations. If you go out in the mountains, please share your observations on the Mountain Information Network (MIN). Photos are especially helpful! Thank you so much for all the great MINs submitted so far! 

Snowpack Summary

A melt-freeze crust on steep solar aspects at treeline and above will soften through the day. On shadier aspects, alpine surfaces are predominantly wind affected, with soft snow still to be found in at lower elevations. Widespread growth of large surface hoar crystals and surface faceting have been reported. These types of crystals (crust, hoar, facets) that develop on the surface as it sits exposed during prolonged periods of high pressure like this often become a problem once buried by the next snowfall.

A couple of layers of feathery surface hoar crystals exist in the upper snowpack. Just 10 cm below the surface, the first of these layers has likely broken down in areas where the surface warmed up on Wednesday. Another patchier layer of smaller crystals may sit beneath 40-60 cm of old wind slab.

The lower snowpack is characterized by a couple of crusts, the most notable of which is sitting near the base of the snowpack, likely surrounded by a weak layer of sugary facets. It is most likely to be reactive to human triggers on south facing slopes and in shallow, rocky areas in the alpine.

Terrain and Travel

  • Make observations and assess conditions continually as you travel.
  • Back off slopes as the surface becomes moist or wet with rising temperatures.
  • Avoid exposure to overhead hazards when solar radiation is strong.

Problems

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.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.