Avalanche Forecast

Archived

Apr 25th, 2014–Apr 26th, 2014

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Regions

Kootenay Boundary.

We are no longer issuing danger ratings for this region due to a lack of field data.Please refer to this blog post for more insight into managing the current conditions.

Confidence

Poor - Due to the number of field observations

Weather Forecast

Synopsis: The weather pattern should remain cool and unsettled through the weekend. Expect periods of light to moderate precipitation mixed with sunny breaks most days. The greatest amount of precipitation should be on Saturday (10-20 mm or cm). Freezing levels should climb to 1600-1800 m each day and rebound to around 1300-1500 m overnight. Ridgetop winds are generally light to moderate from the southwest. It looks like a building ridge of high pressure could bring drier and much warmer conditions early next week.

Avalanche Summary

There are very few observers in the field; however, one observer from the northern part of the region reported several easily triggered wind slabs from steep lee terrain on Thursday.

Snowpack Summary

This is a broad general summary of conditions in the region based solely on recent weather data and previous snowpack information. It should be supplemented with local observations to help assess avalanche danger. Please refer to this document for additional snow and avalanche information and general travel advice. Over the past week we have seen moderate amounts of moist or wet new snow mixed with showers or periods of rain below 1600-1800 m. Westerly winds have likely formed pockets of wind slab at higher elevations in lee of ridges and terrain features. The late January/early February persistent weak layer is deeply buried but could still wake up during periods of heavy precipitation (especially rain) or significant warming and solar radiation. Be particularly wary of this on large open alpine slopes. Cornices are large in some areas and should be given a wide berth.

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.

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.