Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Regions
Banff Yoho Kootenay.
New snow, wind and warmer temperatures are slowly increasing the avalanche hazard. We also have a fair bit of uncertainty about how well the Feb 10th layer is bonding. Treat all steeper terrain with caution.
Weather Forecast
An additional 5-10cm of snow is forecast each day through Thursday accompanied by moderate SW winds. Alpine temperatures in the -15'C to -5'C range with warming temperatures forecast for Thursday.
Snowpack Summary
10cm of new snow today with moderate SW winds. 30-45cm of snow sits on the Feb10th layer comprised of facets, surface hoar, and on solar aspects a sun crust. Test results are generally in the moderate to hard range but still show that propagations are possible in many areas. Some whumphs on this layer today. No shears found in the basal layers.
Avalanche Summary
One size 1.5 skier accidental was reported yesterday on an E aspect at 2350m near Bow Summit which failed on the Feb 10th layer. Some natural loose snow avalanches up to size 1, and a small wind slab triggered with explosives were also reported today. We expect to see a gradual increase in avalanche activity over the next few days.
Confidence
Intensity of incoming weather systems is uncertain
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.