Avalanche Forecast
Issued: Apr 21st, 2019 4:01PM
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 / Light, southwesterly winds / Alpine low -1 C / Freezing level 2200 m.
MONDAY: Rain/alpine flurries; 5-10 mm. / Moderate to strong, southwesterly winds / Alpine high 1 C / Freezing level 2200 m.
TUESDAY: Cloudy with isolated alpine flurries; 1-3 mm. / Light, southwesterly winds / Alpine high 1 C / Freezing level 2200 m.
WEDNESDAY: Sunny / Light, southwesterly winds / Alpine high 2 C / Freezing level 1900 m.
Avalanche Summary
On Saturday, numerous, natural loose wet avalanches up to size 1.5 were reported on steep solar aspects at treeline and above in the afternoon.
A widespread storm slab avalanche cycle to size 3.5 on all aspects in the alpine was reported on Friday. Although not in this region, check out this MIN report from Saturday in Glacier National Park HERE.
Snowpack Summary
30-40 mm of rain has soaked the snowpack at treeline and below. The rain/snow boundary on Friday was around 2100 m. New snow amounts in the alpine will taper rapidly with elevation and likely equate to around 15-25 cm of moist snow at upper elevations adding to the 20-40 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 30-60 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 on Monday may create fresh wind slabs that ‘step-down’ to the recent storm snow, resulting in large avalanches.
- 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: 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 terrain traps such as cliffs and gullies that increase the consequence of small avalanches.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Apr 22nd, 2019 2:00PM
