Avalanche Forecast
Issued: Mar 27th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
cgarritty,
Avalanche Canada
Strong north winds will enter the region Saturday night and their impact is uncertain. Start in initial assessment mode and plan to manage a complex distribution of reactive new wind slabs.
Summary
Confidence
Weather Forecast
Saturday night: Cloudy with continuing flurries bringing about 5 cm of new snow. Winds becoming strong northerly.
Sunday: A mix of sun and cloud. Moderate to strong north winds easing over the day. Alpine high temperatures around -14.
Monday: Becoming cloudy. Moderate southwest winds. Alpine high temperatures around -9.
Tuesday: Cloudy with isolated flurries and a trace of new snow. Moderate southwest winds. Alpine high temperatures around -4.
Avalanche Summary
Reports from the White Pass area over the midweek and again on Friday at Paddy Peak showed fairly minimal wind slab reactivity in areas where wind has actively been moving loose snow around.
Although an uptick in new snow and wind was observed Friday morning in the White Pass area, accumulation and wind since the observation tapered off, likely minimizing new slab development.
What snow remains available for transport in exposed areas may get moved into small new slabs in a reverse loading pattern as north winds take over again Saturday night.
Snowpack Summary
Light new snow amounts and bouts of elevated wind may have formed small new wind slabs in exposed leeward terrain while creating lightly wind-affected surfaces elsewhere.
Previous small wind slabs have largely stabilized, but concern still exists for the ability of large triggers like cornices or machines to trigger older large, hard wind slabs in alpine areas.
There are no deeper concerns around White Pass.
Substantial spatial variability likely still exists in the snowpack around the Tutshi Lake/Paddy Peak area. Terrain here should be assessed on a slope by slope basis, as lingering snowpack weaknesses may still exist.
The Wheaton's continental snowpack is dominated by hard wind slabs overlying sugary facets and depth hoar. It's an untrustworthy snowpack structure that requires conservative terrain selection and diligent travel habits.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Avoid exposure to slopes that have cornices overhead.
- Watch for areas of hard wind slab on alpine features.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Problems
Wind Slabs
Winds will shift north Saturday evening to complicate the distribution of small new wind slabs. Identify leeward slopes likely to hold new slabs if you're entering exposed terrain. Increase caution and carefully scrutinize large old hard wind slabs in high alpine features before committing to lines in bigger terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 29th, 2021 4:00PM
