Avalanche Forecast
Issued: Apr 20th, 2019 6:05PM
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
Strong solar radiation on Sunday may trigger fresh storm slabs at upper elevations; especially on lee features below ridgetops. Large avalanches could run to valley bottoms.
Summary
Confidence
Moderate - Due to the number of field observations
Weather Forecast
SATURDAY NIGHT: Clear / Light, northwesterly winds / Alpine low -6 C / Freezing level 800 m.
SUNDAY: Sunny / Light, southwesterly winds / Alpine high -1 C / Freezing level 2100 m.
MONDAY: Cloudy with light rain/alpine flurries; 5-10 mm. / Moderate, southwesterly winds / Alpine high 0 C / Freezing level 2100 m.
TUESDAY: Cloudy with very light rain/alpine flurries; 0-3 mm. / Light, southwesterly winds / Alpine high -1 C / Freezing level 1800 m.
Avalanche Summary
On Friday, Numerous loose wet and slab avalanches to size 3 on all aspects in the alpine were reported. Natural and human triggered avalanches will remain likely in the alpine on Sunday.
Snowpack Summary
10-25 mm of rain has soaked the snowpack below treeline. The rain/snow boundary on Friday was around 2000 m. New snow amounts in the alpine will taper rapidly with elevation and likely equate to around 10-15 cm of moist snow at upper elevations adding to the 15-40 cm recent snow which overlies a crust everywhere except high elevation, north facing terrain where preserved surface hoar (weak, feathery crystals) may be present in isolated locations down 40-60 cm. A similar layer buried in early April is down 50-80 cm. Smaller storm slab avalanches may step down to one of these deeper weak layers.
Below treeline, snow is disappearing rapidly.
Problems
Storm Slabs
Fresh storm slabs at upper elevations will likely be reactive to human triggers; especially in lee features below ridgetops. Large avalanches could run to valley bottoms.
- Use small slopes without consequence to test the bond of the recent snow.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- Pay attention to changing conditions with elevation/aspect.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
Strong solar radiation may trigger loose wet avalanches on steep terrain; especially at upper elevations where there is new snow.
- Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.
- A moist/wet snow surface, pinwheeling and natural avalanches all indicate a weakening snowpack.
Aspects: North East, East, South East, South, South West, West, North West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Apr 21st, 2019 2:00PM
