The persistent slab problem is less of a concern in this subregion but the amount of serious avalanche activity in adjacent areas has been alarming.
Field observations remain limited, particularly in the alpine. Do not make assumptions. Confirm the snowpack is favorable before committing to serious terrain.
South and west winds over the last few days have led to the development of wind effect and small thin slabs at treeline and above. If initiated, these slabs may be enough to activate the persistent slab.
Light snow and increased winds through Monday will contribute to these slabs.
A 60-100 cm slab overlies mid-pack facets. Caution is advised: avoid start zones and be very wary of overhead hazard.
No new avalanches were observed in Little Yoho Saturday.
On Wednesday, avalanche control on Mount Field and Dennis produced avalanches to size 2.5 on the persistent layer.
Over the past two weeks, many large avalanches have been seen in adjacent areas to the east of the divide. See the BYK bulletin for details.
Expect surface crusts on solar aspects at treeline and below.
At treeline, 70-100 cm of snow overlies the Jan. 30 / Feb. 22 drought layers, which consist of 20-30 cm of weak faceted crystals. These layers have been reactive in tests and recent avalanches in adjacent areas.
In this thicker, western, snowpack region, the facet/depth hoar basal layer is less prominent than it is east of the divide but likely exists in thin areas.
Average snowpack depth at treeline is ~200 cm.
Trace amounts of snow will accumulate overnight Saturday as west winds increase to moderate in the alpine. Treeline temperatures drop to near -10C.
Sunday, flurries continue as winds increase to the strong range and the freezing level approaches 1900m.
Watch for rising freezing levels into the week.
