Avalanche Forecast
Issued: Feb 15th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
ghelgeson,
Avalanche Canada
Potentially thick slabs can be found in wind exposed terrain, especially immediately lee of ridge crest. Caution is needed in the trees right now too, the most recent storm snow may be resting on a spotty layer of surface hoar.
Summary
Confidence
Moderate - Uncertainty is due to the extreme variability of wind effect on the snowpack.
Weather Forecast
We’re moving into a dryer period that is expected to be with us for the foreseeable future. Freezing levels look very reasonable for the middle of February and there is a fair amount of sun in the forecast for the work week.
SATURDAY NIGHT: Freezing level around near valley bottom, moderate west/northwest wind, 1 to 5 cm of snow expected with the highest terrain potentially receiving as much as 12 cm.
SUNDAY: Broken cloud cover, freezing level around 1300 m, light to moderate west/southwest wind, trace of snow possible.
MONDAY: Scattered cloud cover, freezing level around 1000 m, light to moderate northwest wind, no significant precipitation expected.
TUESDAY: Scattered cloud at dawn, clearing by sunset, freezing level rising to about 1000 m, light north/northwest wind, no significant precipitation expected.
Avalanche Summary
On Friday wind slab avalanches were sensitive to human triggering and explosive control work to size 1.5 on lee aspects above 1900 m.
Explosive work Wednesday produced size 1.5-2 wind slab and cornice avalanches. Several small (size 1) natural and skier-triggered wind slab avalanches have been reported on east/northeast aspects in the alpine over the past few days. At least one of these occurred near treeline and was reported to have slid on a crust buried around 20 cm below the surface.
Snowpack Summary
The weekend storm produced 10 to 20 cm of new snow which is expected to further wind slab development in lee features at alpine and upper treeline elevations. The new snow is failing of a variety of surfaces: hard wind slabs around ridgetops and northerly alpine features, soft slabs and 10-15 cm of lower density snow in sheltered terrain, a thin sun crust on solar aspects, and scoured features in exposed terrain. Spotty surface hoar has also been reported under the storm snow.
A thick rain crust to mountain top sits below 25-45 cm of recent storm snow in the east of the region and 40-100 cm in the west. Recent avalanches slid on the crust or released within the storm snow. However, recent information indicates the bond at the crust is improving. Weak facet/crust layers near the base of the snowpack have not been an active avalanche problem recently.Â
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
Problems
Storm Slabs
As of Saturday afternoon the weekend storm has produced 10 to 20 cm of new snow, a bit more is expected Saturday night. In wind exposed terrain this snow is being formed into slabs by ongoing winds from the southwest, west and northwest. In wind sheltered terrain the new snow may rest on a layer of surface hoar which could make it touchier than expected, especially in the trees.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 16th, 2020 5:00PM
