Avalanche Forecast
Issued: Apr 17th, 2017 4:00PM
The alpine rating is Wind Slabs, Cornices and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeCooler weather and flurries expected the next 24 hrs followed by a clearing trend for Thursday.
Summary
Weather Forecast
Freezing levels will drop to valley bottom through the night as showers and flurries move into the region. Moderate West winds follow they system. Clearer skies for later in the week.
Snowpack Summary
A thin breakable melt freeze crust now caps the 20-50cm of snow from last week on all aspects expect due North above 2300 m. Stubborn windslabs may be found on Northerly aspects in the high alpine. At tree line and above the mid-pack is a 120cm+ firm slab overlying weaker basal facets in much of the region.
Avalanche Summary
No new avalanches reported today. On Sunday: Skiers triggered a sz 2 slab at 2500m on the S aspect of Mt Jimmy Simpson 40 deep over a crust on a 30 degree slope. Also late Sunday in the heat of the day, two size 3's and one size 2 from thin snowpack areas (lookers right of isolated col), SW aspect, 2500 m, wide propagations, slid on ground.
Confidence
Problems
Wind Slabs
The windslabs created on Friday by moderate West wind is now capped with a thin melt freeze crust on all aspects except due North. Prior to the new surface crust, these slabs were failing on an older crust 40 cm down on solar aspects.
- If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: North, North East, East, South East.
Elevations: Alpine.
Likelihood
Expected Size
Cornices
Cornices continue to fail. Minimize your time underneath these and remember that a cornice failure could also trigger the deep persistent slab on the basal facets.
- Stay well to the windward side of corniced ridges.
- Avoid travel on slopes that are exposed to cornices overhead.
Aspects: North, North East, East, South East.
Elevations: Alpine.
Likelihood
Expected Size
Persistent Slabs
The snowpack is gaining strength, however the facets deeper in the snowpack remain a concern in thin alpine areas and where a cornice could trigger the slope. These facets do exist in isolated treeline areas, but are not currently a problem.
- Choose the deepest and strongest snowpack areas on your run.
- Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 18th, 2017 4:00PM