Avalanche Forecast
Issued: Apr 17th, 2019 9:09PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Loose Wet.
jsmith,
Avalanche Canada
UPDATED Forecast for Thursday! The storm has arrived earlier than expected, fresh storm slabs reactive to human triggers may form by end of day at treeline and above.
Summary
Confidence
Moderate - Timing of incoming weather systems is uncertain
Weather Forecast
WEDNESDAY NIGHT: Partly cloudy / Light, westerly winds / Alpine low 0 C / Freezing level 2000 m.
THURSDAY: Showers and alpine flurries; 5-10 mm. / Moderate, southwesterly winds / Alpine high 4 C / Freezing level 2500 m.
FRIDAY: Rain (snow above roughly 2000 m); 15-25 mm. / Strong, southwesterly winds / Alpine high 2 C / Freezing level 2200 m.
SATURDAY: Mix of sun and cloud / Light, northwesterly winds / Alpine high 1 C / Freezing level 2000 m.
Avalanche Summary
On Tuesday, two naturally triggered size 1.5 storm slab avalanches 25 cm deep were reported on northwest aspects 2200-2400 m.
On Sunday, a skier triggered a size 1.5 wind slab avalanche on a steep convex roll at 2150 m and explosives triggered a size 2 storm slab avalanche at 2350, both avalanches occurred on a northeast aspect.
A natural avalanche Sunday was observed north aspect at 2300 m. The size 2 storm slab avalanche failed on surface hoar around 40-50 cm deep likely buried early April. This isolated layer may see increased stress as temperatures penetrate the snowpack.
Snowpack Summary
Sun and rising freezing levels are settling the 20-40 cm recent snow on all slopes to 2100 m and sunny slopes in the alpine. Where dry snow remains, pockets of reactive storm snow may be found around ridges and lee features. A total of 50-65 cm snowfall through April now overlies a melt-freeze crust and, in select areas, facets or surface hoar. Below treeline snow is disappearing rapidly.
Problems
Storm Slabs
Additional snow, wind, and warm temperatures on Thursday may activate recently formed storm slabs at treeline and above.
- Use small slopes without consequence to test the bond of the recent snow.
- Pay attention to changing conditions with elevation/aspect.
- Be careful with wind-loaded pockets, especially near ridge crests and roll-overs.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
Rising freezing levels and the potential for rain on dry snow may initiate a loose wet avalanche cycle by the end of day.
- A moist/wet snow surface, pinwheeling and natural avalanches all indicate a weakening snowpack.
- Avoid terrain traps such as cliffs and gullies that increase the consequence of small avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Apr 18th, 2019 2:00PM
