Avalanche Forecast
Issued: Dec 6th, 2018 4:30PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
cgarritty,
Avalanche Canada
Conditions have been steadily improving. If you're looking for trouble, you might still find it around steeper, protected solar aspects where surface hoar coexists with a sun crust.
Summary
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Thursday night: Cloudy with clear periods. Light southwest winds.Friday: A mix of sun and cloud. Light southwest winds. Alpine high temperatures around -8, slightly cooler at lower elevations under a mild temperature inversion.Saturday: Mainly cloudy. Light southwest winds. Alpine high temperatures around -7, cooler at lower elevations with a lingering mild temperature inversion.Sunday: Mainly cloudy with thicker low level cloud. Light south winds, increasing to strong at alpine elevations. Alpine high temperatures around -4, cooler at lower elevations under a more pronounced temperature inversion.
Avalanche Summary
Several small natural wind slab releases were observed in the Whitewater area on Wednesday. These occurred on steep alpine features and may have been a product of recent northerly winds. Big thanks go out to our contributors to the Mountain Information Network. Please continue to post your observations here.
Snowpack Summary
Days of cold temperatures and increasingly clear skies have been growing a new layer of feathery surface hoar on the surface. Winds may have scoured some of this surface hoar from alpine slopes. The cold has also been transforming our roughly 20 cm of aging storm snow on the surface into a layer of faceted (weak, sugary) snow. At treeline, the height of snow is between about 100 and 140 cm. At 50 to 70 cm below the surface, there is a closely stacked pair of buried persistent weak layers. The upper layer consists of surface hoar (feathery crystals) in most places, but may present as a sun crust on steep south facing slopes. The deeper layer features similar surface hoar distribution over a more widespread temperature crust. These layers have shown ongoing but variable reactivity in snowpack tests in the past week. Both surface hoar layers are thought to be widespread at treeline and may also extend into sheltered alpine features.At the base of the snowpack is a thick melt-freeze crust that formed near the end of October. Observations of reactivity at this crust have been limited, but it has acted as the failure plane in several large avalanches in the neighbouring South Columbias.
Problems
Persistent Slabs
Our 40-80 cm deep weak layer is slowly becoming less reactive, but it's still a concern in steeper, protected slopes around treeline and lower alpine. Special attention should be given to solar aspects where surface hoar may coexist with a sun crust.
Avoid steeper open slopes and convex rolls at treeline where buried surface hoar may be preserved.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 7th, 2018 2:00PM
