Avalanche Forecast
Issued: Jan 25th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.
CB,
Avalanche Canada
Watch for fresh wind slabs forming Thursday with new snow and winds forecast. These could be touchy to rider triggering.
Use caution in shallow, rocky areas for triggering a weak layer at the base of the snowpack.
Summary
Confidence
Moderate
Avalanche Summary
On Wednesday we observed several natural avalanches, size 2-2.5 along the highway corridor in south facing terrain. Likely triggered by wind loading and sun effect midday.
Backcountry reports, also on Wednesday, of rider triggering soft slabs, up to size 1, down 30-40cm on a sun crust. And sluffing in steep terrain.
A field team on Connaught/Lookout triggered a sz 1 wind slab on Monday, which stepped down to the Jan 3 surface hoar. They also observed several sz 1 loose/dry avalanches on the N Face of MacDonald, running in extreme terrain.
Cheops North 4 ran sz 2 Monday morning, while Frequent Flyer ran sz 2 on Sat into the creek.
Near neighbours have reported large natural and rider triggered avalanches up to sz 3, both wind slabs and deep persistent slabs. See MIN's for details.
Snowpack Summary
Reactive wind slabs are popping out at Treeline and Alpine elevations, stepping down into the Jan 3 persistent weak layer. Thin sun crust down 30-40cm. Good skiing below treeline with small amounts of unconsolidated storm snow keeping the surface soft.
The mid-pack facets are slowly rounding and gaining strength, while the basal facets and Nov 17 facet/SH/crust weakness are still reactive when isolated in snowpack tests.
Weather Summary
Unsettled weather Thurs/Fri with flurries bringing light/moderate snowfall and light/mod W/NW winds.
Tonight: Cloudy w/flurries, 2 cm, Snow level 800m lowering to valley bottom this evening, Moderate W winds.
Thurs: Cloudy w/flurries, Alp high -4*C, 1500m FZL, moderate gusty W winds
Fri: flurries, 5-10cm snow, Alp high -6*C, 1200m FZL, moderate gusty N winds
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Problems
Wind Slabs
Moderate westerly winds forecast on Thursday will build upon wind slabs formed earlier in the week.
These slabs are particularly reactive on convex rolls at ridge-line, lee areas, and cross loaded features.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
This layer is buried ~40cm and will be most reactive at ridgeline or in open lee features where new wind slab has formed on top of it. If triggered, this slab has the potential to step down to the deep persistent layer.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
The Nov 17 layer, which consists of a faceted crust and decomposing surface hoar, highlights a weak basal snowpack. Be cautious in steep, rocky areas with thin snow coverage, where the majority of the snowpack is weak and faceted.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 26th, 2023 4:00PM
