Avalanche Forecast
Issued: Apr 13th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Cornices.
zryan,
Avalanche Canada
Carefully assess your line for wind slab hazard. Remember that small avalanches can have large consequences in the wrong terrain.
Cornices are large and exposure to them should be minimized, especially during warm or sunny weather.
Summary
Confidence
Moderate - Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack.
Weather Forecast
WEDNESDAY NIGHT: Clear skies, no precipitation. 20-40 km/h wind from the northeast, treeline temperatures drop to -15 C.
THURSDAY: Mainly clear skies, high cloud building into the afternoon. No precipitation, light wind from the north, treeline temperatures reach -8 C.
FRIDAY: Cloudy with light flurries. 10-25 km/h wind from the west, treeline temperatures around -10 C.
SATURDAY: Cloudy with flurries, up to 5 cm of accumulation. 15-30 km/h wind from the southwest, treeline temperatures around -8 C.
Avalanche Summary
A very large cornice-triggered wind slab avalanche (size 3) was observed near White Pass on Tuesday. This avalanche occurred on an east aspect in the alpine.
Several small human-triggered wind slabs (size 1) were reported during the outflow wind event on Monday and Tuesday. A few other large cornice failures were observed on Sunday.
This MIN report from Tuesday paints an excellent picture of the lingering wind slab problem and conditions in the White Pass area.
Snowpack Summary
Strong northerly wind has affected most surfaces and left hard wind slabs in alpine terrain. Sun crusts are found up to 1400 m on south and west-facing slopes, while surfaces on other aspects are dry. The mid-snowpack is generally strong, overlying weak basal facets at the base of the snowpack.Â
Terrain and Travel
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- Avoid exposure to slopes that have cornices overhead.
- Cornices often break further back than expected; give them a wide berth when traveling on ridgetops.
Problems
Wind Slabs
Recent outflow wind has left pockets of hard wind slab on south-facing alpine slopes. Be cautious around ridge crests and steep rolls.
Aspects: South East, South, South West, West.
Elevations: Alpine.
Likelihood
Expected Size
Cornices
Cornices are large this time of year and may have been weakened by recent cold temperatures. Exposure to cornices should be minimized, especially during periods of warm temperatures or strong sun.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 14th, 2022 4:00PM
