http://www.pc.gc.ca/apps/scond/Cond_E.asp?oID=26206&oPark=100092Special Public Avalanche Warning has been issued for Jasper National Park due to dangerous avalanche conditions.
Weather Forecast
Light flurries over the next few days will accumulate up to 10cm of new snow. Temps to remain between -3 to -10 in the Alpine with light (1-25km/hr) SW winds. Freezing levels could go as high as 1700m on Monday.
Snowpack Summary
25cm HST in the past 5 days along the Columbia Icefields, previous 35km/hr SW winds have built, yet another, layer of windslab TL and ALP. A rain crust (up to 20cm) exists below 1900m. The denser upper snowpack overlies a weak faceted lower pack, making for very tricky and dangerous avalanche conditions.
Avalanche Summary
Several avalanches up to Sz 3 occurred yesterday along the Parkway, one of which dusted the highway from Mt. Wilson. Several avalanches reported today in the backcountry terrain adjacent to the Marmot Ski area.Widespread whumphing and shooting cracks were noted on all elevations.
Confidence
Due to the number of field observations on Saturday
Problems
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.
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.