Avalanche Forecast
Issued: Apr 17th, 2019 6:47PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
jsmith,
Avalanche Canada
Additional snow and wind on Thursday may activate recently formed storm slabs at treeline and above. Consider the hazard to be one-step higher if localized areas receive more than 15 cm of snow during the day on Thursday.
Summary
Confidence
Moderate - Timing of incoming weather systems is uncertain
Weather Forecast
WEDNESDAY NIGHT: Cloudy / Light, southwesterly winds / Alpine low -2 C / Freezing level 1500 m.
THURSDAY: Snow above roughly 1800 m; 3-10 cm. / Moderate to strong, southwesterly winds / Alpine high 0 C / Freezing level 2000 m.
THURSDAY NIGHT: Snow above roughly 1400 m; 15-20 cm. / Strong, southwesterly winds / Alpine low -2 C / Freezing level 1500 m.
FRIDAY: Cloudy with flurries; 3-5 cm. / Light, westerly winds / Alpine high -1 C / Freezing level 1700 m.
SATURDAY: Sunny / Light, northwesterly winds / Alpine high 0 C / Freezing level 1800 m.
Avalanche Summary
On Tuesday, numerous of naturally triggered size 2 persistent slab avalanches were reported on all aspects in the alpine.
A natural avalanche cycle to size 2.5 was reported on Monday. Avalanches to size 2.5 were observed on all aspects above 2000 m failing on a crust or, in one case, isolated surface hoar, with crown depths of 70 cm. Three remotely triggered avalanches size 1.5-2 avalanches were triggered on east aspects around 2100-2200 m failing on facets, also with crown depths of 70 cm.
On Sunday a small (size 1) natural storm slab was observed on an east aspect at 2600 m.
A week ago Tuesday, a small (size 1) slab avalanche 30 cm deep was remotely triggered by a skier from 80 m away on a northeast aspect at 2250 m. A layer of small surface hoar below the most recent snow may have been the weak layer. This layer is now buried approximately 70 cm deep in the snowpack and may see increases stress as temperatures penetrate the snowpack.
Snowpack Summary
Sun and rising freezing levels are settling the 15-40 cm recent snow on all slopes to 2000 m and sunny slopes in the alpine. Where dry snow remains, slabs have developed around ridges and lee features. Around 70 cm snowfall through April now overlies a melt-freeze crust and in isolated areas, facets or surface hoar. Natural avalanches on Monday failed at this interface.
Below treeline snow is disappearing rapidly.
Problems
Storm Slabs
Additional snow and moderate to strong southwesterly winds on Thursday may activate recently formed storm slabs at treeline and above.
- Pay attention to changing conditions with elevation/aspect.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- Use small slopes without consequence to test the bond of the recent snow.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 18th, 2019 2:00PM
