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 3rd, 2012–Dec 4th, 2012

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

Regions

Purcells.

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Overnight and Tuesday: Light to locally moderate snowfall / Extreme southwest winds / Freezing level at 1500mWedesday: Light snowfall / Strong to extreme southwest winds / Freezing level at surfaceThursday: Trace amounts of snow / Light southwest winds / Freezing level at surface

Avalanche Summary

No new avalanches to report. This may speak more to a lack of observations than actual conditions. Any field observations can be sent to [email protected].

Snowpack Summary

Over the last few days snowfall amounts have been highly variable throughout the region and windslabs may exist at higher elevations. Reports indicate that up to 50cm of recent storm snow may now sit above a surface hoar layer that developed last week and was buried on the 28th. Although not necessarily widespread in the region, releases on this layer are likely if you have it in your area. There is a surface hoar layer that developed during mid-november was reported to be active last week, but has not been reactive during the recent storm. There is a rain crust near the ground that we're calling the early November crust. There are some facets below it, or it may appear as a sandwich of crusts and facets, but it's been reported  as unreactive at this time. There is still a sharp transition in snow depth from treeline to below treeline making back-country travel challenging under 1300 m in elevation. In general, significant variations in snowpack structure exist across the region. Digging down and making your own observations will be critical to safe slope selection. Any observations from the field are welcome at [email protected].

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.