Avalanche Forecast
Issued: Apr 21st, 2019 4:10PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Loose Wet.
jsmith,
Avalanche Canada
New snow and strong winds may create small wind slabs that when in motion, step-down to the recent storm snow, resulting in large avalanches.
Summary
Confidence
Moderate - Due to the number of field observations
Weather Forecast
SUNDAY NIGHT: Clear / Moderate, southwesterly winds / Alpine low -3 C / Freezing level 2100 m.
MONDAY: Rain/alpine flurries; 5-10 mm. / Strong, southwesterly winds / Alpine high 1 C / Freezing level 2100 m.
TUESDAY: Mix of sun and cloud with isolated alpine flurries; 1-3 mm. / Light, southwesterly winds / Alpine high 1 C / Freezing level 2000 m.
WEDNESDAY: Sunny / Light, westerly winds / Alpine high -2 C / Freezing level 1500 m.
Avalanche Summary
No new avalanches were reported on Saturday.
On Friday, a widespread storm slab natural avalanche cycle to size 3 occurred on all aspects in the alpine. This new snow will need several days to settle and bond to the old snow surface.
Snowpack Summary
10-25 mm of rain soaked the snowpack below treeline. The rain/snow boundary on Friday was around 2000 m. Strong southwesterly winds heavily loaded lee aspects. New snow amounts in the alpine will taper rapidly with elevation and likely equate to around 10-20 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
Wind Slabs
New snow and strong winds may create small wind slabs that when in motion, ‘step-down’ to the recent storm snow, resulting in large avalanches.
- 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: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
If temperatures remain warm, loose wet avalanches are still possible on cloudy days due to the ‘green-house’ effect.
- A moist/wet snow surface, pinwheeling and natural avalanches all indicate a weakening snowpack.
- Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Apr 22nd, 2019 2:00PM
