Confidence
Fair - Timing or intensity of solar radiation is uncertain on Saturday
Weather Forecast
Overnight and Thursday: The Northwest flow is expected to continue to push the cold arctic air to the East. Northwest winds moderate overnight becoming strong during the day. No precipitation is expected tonight, and light snow falls of 1-2 cms are expected on Thursday. Alpine temperatures gradually warming on Thursday and freezing levels rising to about 1200 metres.Friday: No precipitation is expected as a high pressure system in the South influences most of the interior mountain ranges. Expect clear skies or high overcast in the alpine and valley cloud. Freezing level at about 1300 metres.Saturday: High pressure should continue to influence. No precipitation expected, and freezing level at about 1200 metres.
Avalanche Summary
Some loose snow sluffing from steep terrain. Natural wind slabs up to size 2.5 were running full path on the East side of Glacier National Park in the highway corridor.
Snowpack Summary
Recent storm snow amounts over the past few days are 30 to 40 cm with as much as 60cm reported. Over the weekend, this low density storm snow started to settle into more of a cohesive slab, although little activity was reported through the weekend. Below the new snow is a suncrust on steep southerly facing slopes and a surface hoar layer at treeline and lower elevations (but it has a patchy distribution). Early January surface hoar is now around 60 - 80 cm deep and is reported to be patchy. It is most likely to be preserved on shady slopes below treeline.
Problems
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.