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, 2018–Dec 5th, 2018

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

Lizard-Flathead.

Strong to extreme northwest wind Tuesday night is expected to create fresh wind slabs in the alpine which may continue to fail naturally Wednesday. Wind slab avalanches in motion may step down to deeply buried weak layers producing large avalanches.

Confidence

Low - Due to the number of field observations

Weather Forecast

The high amplitude ridge sitting off the BC Coast is expected to deflect any potential storm systems away from the province this week. The forecast period is marked by cooler temps, clear skies and no significant precipitation with no change expected for the foreseeable future.TUESDAY NIGHT: Freezing level at valley bottom, light southerly wind at most elevations, strong to extreme northwest wind at ridgetop, no significant precipitation expected. WEDNESDAY: Broken cloud cover, freezing level at valley bottom, light variable wind, no significant precipitation expected. THURSDAY: Clear sky, freezing level at valley bottom, light variable wind, no significant precipitation expected.FRIDAY: Clear sky, freezing level at valley bottom, light southwest wind at low elevations, moderate northwest wind at ridgetop, no significant precipitation expected.

Avalanche Summary

No new avalanche activity to report from Monday.  On Sunday a human triggered avalanche was reported in Cornice Bowl.  We received some updated information about the size of the avalanche. It's been determined that the northwest facing feature at 2300 m produced a size 2 avalanche that ran on the early November crust. The crown was 30 to 40 cm deep, approximately 20 m wide and 300 m in length. Check out the initial report here.  Explosive control also triggered a few storm slabs up to size 2 from northeasterly aspects 1800-2000 m. If you're in the backcountry and have observations to share, please post to the Mountain Information Network.

Snowpack Summary

Up to 55 cm of recent snow sits on a combination of crust and surface hoar. The crust is most prevalent at and above treeline and is likely most problematic on north facing features, especially those that are large and planar in nature.The surface hoar is tricky to pin down because it is quite spotty in distribution, but it appears to be most prevalent on sheltered slopes at and above treeline. At the bottom of the snowpack lies another crust with weak sugary facets around it. There is a great MIN Report here that provides a good visual representation of the current snowpack.At treeline the average snowpack depth is 80 cm, with only thin coverage at lower elevation.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.