http://www.pc.gc.ca/apps/links/goto_e.asp?destination=http://www.mountainconditions.com/reports/special-public-avalanche-warning-banff-yoho-kootenay-jasper-feb-17-20-2017Special Public Avalanche Warning has been issued for Jasper due to touchy conditions and newly open terrain around the ski area. Human triggering has the potential to produce large avalanches.
Weather Forecast
Temperatures are to drop below freezing tonight and remain there through the weekend. Light flurries with 5 cm new snow possible by Sunday. Winds are forecast to be Light SW.
Snowpack Summary
This unsupportive melt freeze crust below tree-line. The upper snowpack is failing on the weak and faceted lower pack. Widespread whumphing and shooting cracks were noted on all elevations. The snowpack is untrustworthy.
Avalanche Summary
1 Size 2.5 natural avalanche reported in the Whistler Creek drainage on steep NE tree-line slope. No other activity was observed or reported today.
Confidence
Due to the number and quality of field observations on Saturday
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.