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 6th, 2012–Dec 7th, 2012

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

Regions

Little Yoho.

Wind effect starts above 2400m. Good ski quality reported on sheltered slopes. SH

Weather Forecast

Only a few cm of snow Friday, with light alpine NW winds and valley bottom freezing levels.  The weekend looks much the same until Sunday when winds may jump into the strong range again.

Snowpack Summary

Strong SW winds from Tues/Wed. produced wind slabs in exposed alp. and treeline locations. Sunshine backcountry has received approx. 60cm since Dec.1 with lesser amounts in the Lake Louise area. The Nov.6 crust is approximately 20cm above the ground up to approx. 2600m.  Forecasters on Ferris Glacier (Crowfoot Peak) found 130-180cm on the ice.

Avalanche Summary

Explosive control on Sunshine Road only produced 1 sz.2.5 on Mount Bourgeau (NE asp, 2500m)  (photo) (francais) which stepped to the Nov 6 crust and was approx.1m deep. Forecasters on Crowfoot peak saw 1 sz.3 & 1 sz.2  on high NE facing terrain on Vulture Peak which in spots stepped to glacial ice within the last 48-72 hrs.

Confidence

Due to the number and quality of field observations

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.