Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Regions
Jasper.
A bit warmer still on Sunday potentially making triggering a bit more likely. Persistent slabs that begin to be encountered at treeline, and are more developed in the Alpine, make it tough to travel with confidence.
Weather Forecast
Warm, moist air will continue to override the cold arctic air over the Jasper region through Sunday with a chance of a few flurries in the early AM and cloud for the day. Freezing levels will climb to near 2300m and winds should back a bit and shift to the North. Monday winds should shift to the South but temps will cool a bit.
Snowpack Summary
10-15cm of recent snow has blown into thin slabs TL and above. Old slabs, 10-40cm deeper, sit on a weak layer of facets or surface hoar TL and above. In sheltered areas the new snow sits a weak,faceted upper snowpack at all elevations. A strong mid snowpack crust is providing strength but is weakening. The lower snowpack continues to lose strength.
Avalanche Summary
No new avalanche activity seen since Thursday when a sz 2 slab 20cm deep and 50m wide likely failed on the Dec 18 persistent layer. This shallow slab ran a few meters before stepping down another 40 cm (likely through weak facets to the November 27 mid-pack crust). All of this ran 70m to a cliff triggering a small slab below.
Confidence
Freezing levels are uncertain on Sunday
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.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.