Avalanche Forecast
Issued: Jan 5th, 2019 4:18PM
The alpine rating is Storm Slabs and Deep Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
High -
Weather Forecast
SATURDAY NIGHT: Mainly cloudy with isolated flurries, moderate southwest winds, alpine temperature -4 CSUNDAY: Cloudy with isolated flurries, moderate southwest winds, alpine temperature -3 C, freezing level 1200 m.MONDAY: Mix of sun and cloud, light to moderate west winds, alpine temperature -10 CTUESDAY: Cloudy with sunny breaks, light southwest winds, alpine temperature -6 C
Avalanche Summary
Evidence of a widespread natural avalanche cycle was observed on Friday. Storm slabs were reactive to skier traffic and explosives, producing large (size 2 to 3) avalanches with depths around 40 cm. A couple avalanches were observed on the deeper layers described in the snowpack summary.
Snowpack Summary
The recent storm dropped variable snowfall amounts across the region. In the north, upwards of 100 cm of snow fell. In the remainder of the region, around 40 to 60 cm of snow accumulated. The snow fell with strong westerly winds, so the deepest and touchiest deposits will likely be in lee terrain features. The freezing level rose to around 1500 m on Friday, so expect to find wet snow or a frozen crust below this elevation.All this snow is loading a weak layer that formed during the dry spell in early December. It is around 80 to 120 cm deep. The layer is composed of weak and sugary faceted snow, feathery surface hoar crystals, and on south aspects also a sun crust. The base of the snowpack is composed of weak faceted snow at alpine and treeline elevations. These basal weak layers have been producing large avalanches as recently as December 31. Human triggering any of these layers is most likely on slopes that didn't previously avalanche and on slopes that have variable snowpack depth, such as rocky alpine features.
Problems
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Jan 6th, 2019 2:00PM