Avalanche Forecast

Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast. Uncertainty is due to extremely variable snowpack conditions reported through the region.

SATURDAY NIGHT: Partly cloudy, light north wind, low temperatures around -15 C.

SUNDAY: Mostly sunny, light southwest wind, high temperatures around -10 C.

MONDAY: Cloudy with some light flurries, light southwest wind, high temperatures around -8 C.

TUESDAY: Light flurries with up to 5 cm of new snow, moderate south wind, high temperatures around -8 C.

Several large natural avalanches were recently reported at Chappel Creek (see this MIN report). These avalanches occurred on south aspects at treeline elevations. Based on the depth of these avalanches, they likely occurred on the recently buried surface hoar and/or sun crust layers. These photos suggest a persistent slab avalanche problem may exist, but we are uncertain about the details of this problem. Extra caution should be taken on steep treeline terrain around Blue River and Valemount where enough snow sits above this weak layer to produce dangerous avalanches.

Otherwise some small wind slab and dry loose avalanches have recently been observed in steep alpine terrain.

The alpine is wind-affected and lower elevations are capped by a hard rain crust. Reports suggest this crust extends up to 1400 m to 1700 m in different parts of the region. Sheltered areas at treeline likely have 15-40 cm of low density snow from earlier this week.

The main concern (and uncertainty) is whether this recent snow is bonding to a widespread buried surface hoar layer and/or sun crusts. In most areas this snow has probably not developed into a concerning slab, with the exception of the Blue River and Valemount areas where there has been more snowfall on this layer. The most likely terrain for this problem is around treeline elevations where the snowpack has not been affected by wind or rain (see the photos in this MIN report).

Down near the ground remains a thick rain crust with sugary facets above and below from early November. While we have not seen much reactivity on this layer, it continues to produce occasional hard results in snowpack tests. It may be reactive to human triggers on shallow rocky slopes in the alpine or alpine-like features at treeline.

• Investigate the bond of the recent snow before committing to your line.
• Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
• Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
• Use caution on large alpine slopes, especially around thin areas that may propagate to deeper instabilities.