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

Nov 25th, 2013–Nov 26th, 2013

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

Regions

Purcells.

This forecast has been prepared with limited observation data. If you're out in the field, please send information to:[email protected]

Confidence

Poor - Due to the number and quality of field observations

Weather Forecast

Continued mild temps for the forecast period.  No precipitation in sight for the next 3 days. Warm air aloft will slowly be replaced by more seasonal cooler temps in the next few days.

Avalanche Summary

No recent avalanche activity has been reported. Skiers or sledders might trigger this deep weak layer although no recent reports of activity have been received. The likelihood of triggering is decreasing, however the consequences could be huge.

Snowpack Summary

Snowpack depths at tree line hover between 70-100 cm, and 100 to 120 cm in the alpine, except in heavily wind loaded locations.  A surface hoar layer has been identified at other locations in the Columbia ranges between 60and 120 cm from the surface and appears to be drainage specific.  So far it's not been reported in the Purcells. If you've found it, please let us know.Deeper in the snowpack near the base is a melt-freeze / rain crust that formed in October. This is generally found 70-110 cm down, with facetted (sugary) crystals above and below that are poorly bonded. The crust/ facet combo may be more predominant on Northerly aspects and allow for wider propagations, especially in places that have smooth ground cover (glacier ice, grassy slopes, rock slabs etc.).Snowpack conditions may change and deteriorate if temperatures rise in the alpine.

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.