Avalanche Forecast
Issued: Feb 16th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
conrad janzen,
Parks Canada
Triggering wind slabs continues to be the main concern, however recent wind loading has also caused large sluffs in gullies, several natural cornice failures and failures on the deep persistent layer. Continue to choose terrain with low consequences.
Summary
Weather Forecast
Moderate NW alpine winds with light flurries are forecast on Monday with alpine temperatures between -15 and -18 C. Winds become light and shift to the N on Tuesday as a clearing trend occurs. Wednesday is also clear but temperatures will rise to near freezing.
Snowpack Summary
Extensive wind effect in the alpine with wind slabs at ridge tops and in lee areas. Up to 35cm of snow over the last few days sits over a well settled upper and mid-pack. In many areas the lower snowpack consists of weaker facets and depth hoar that are still producing moderate shears in snowpack tests. The Feb 1 crust is present below 1900m.
Avalanche Summary
A few natural cornice failures and wind slab avalanches up to size 2.5 were reported Sunday as well as ski cutting and explosive triggered wind slabs up to size 2 at the local ski areas. On Saturday a skier triggered size 3 was reported on Copper Mountain and an explosive triggered size 3 occurred at Sunshine that both failed on the basal facets.
Confidence
Freezing levels are uncertain on Wednesday
Problems
Wind Slabs
Recent strong W winds have created wind slabs near ridge tops and in lee areas of the alpine, with isolated wind slabs down into treeline. Avoid wind loaded areas and watch for freshly loaded cornices up high for the next day or two.
- Caution on open steep slopes at treeline and above that have been exposed to wind loading.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Several large avalanches failing on the basal facet/depth hoar have been observed in the past week. These can be hard to predict but triggering is more likely in areas with a thin snowpack (~150cm) where the basal facets and depth hoar are prominent.
- Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 17th, 2020 4:00PM
