Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Sunshine, West Side 93N.
Expect the hazard to rise through the weekend as a reasonably vigorous weather system brings snow...
As elevated winds continue, expect further slab development at upper elevations Saturday ... and perhaps more of concern at lower elevations into Sunday.
For the season, this could be a relatively large hit to the weak layers....
Confidence
Moderate
Avalanche Summary
Visitor Safety team members skied around Little Crowfoot today finding lots of wind and wind effect with wind loading predictably found in the lee terrain. Good skiing on both south and north aspects with no avalanches to report.
Lake Louise and Visitor Safety staff traveled parts of the Pumpkin Traverse Thursday and reported ongoing wind transport, wind effect and triggered 2 size 1 slabs 10-20 cm deep on a crust in W facing alpine terrain.
Snowpack Summary
5-10cm of snow has come in over the last three days. Sun crusts and moist snow have been found on steep solar slopes while isolated wind slabs can be found in the high alpine. All of this sits on 10-15 cm of facetted snow over the Feb 3 crust that exists on all but N aspects above 2500m. Below this, weak facet layers can be found in the mid and lower snowpack. Generally, thin snowpack values for this time of the year: range is from 80 to 120cm at 2000m.
Weather Summary
A cold front swept south across the region Friday afternoon: light snow is expected overnight (5cm) with strong SW winds and TL lows near -7C.
Winds shift west Saturday morning. Light snowfall to bring 1-5 cm before dark with temps steady.
Winds back to SW Saturday night, 10 - 15cm is possible through Sunday midnight, winds spike to extreme.
Cooling Monday.
For more information see AvCan's Mt Wx Fx.
Terrain and Travel Advice
- Watch for signs of slab formation throughout the day.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Avalanche Problems
Deep Persistent Slabs
Several persistent weak facet layers exist in the mid-pack as well as at the bottom of the snowpack. Sporadic avalanche activity continues on these layers mainly in thin snowpack, rocky, and steep locations in the alpine. As a guide, use extra caution when the Feb 3 crust becomes thin or disappears.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Unlikely - Possible
Expected Size: 1.5 - 2.5
Wind Slabs
Expect to find small wind slabs in high alpine lee terrain. These slabs generally overlie faceted snow and/or a crust. As moderate to strong west and southwest winds continue through the weekend expect incoming snow amounts of 10-25 cm to contribute to slab development.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 2