Purcells

Fair

Thursday: Arctic air surges south giving colder and drier weather. Expect a mix of sun and cloud with increasing cloud later in the day. Alpine temperatures should be around -15 to -20. Winds are light to moderate from the northwest-west. Friday: Light snow should begin Thursday night with a few cms expected through Friday. The freezing level is at valley bottom and winds are moderate from the west-southwest. Saturday: Lingering flurries in the morning, then clearing. The freezing level is at valley bottom and winds are light from the northwest.

Several small skier controlled avalanches (size 1) were reported on Tuesday. These appeared to be thin wind slabs in exposed north or east facing terrain.

Small amounts of recent storm snow are beginning to add up on top of the sugary facets from early December. Snowpack depths at tree line currently vary from 100- 130 cm and reports speak of severe scouring on the windward side of ridges, moving snow onto lee sides and creating dense wind slabs. A persistent weakness of buried surface hoar and facets is down approximately 20-50cm. This layer has been producing variable results with snowpack tests. Recent reports indicate that the new storm/ wind slab is becoming reactive with warming temperatures and additional loads. At the base of the snowpack are weak facets and depth hoar combined with a crust from early October. This deep persistent weakness may be stubborn to trigger, especially in deeper snowpack areas, but the sensitivity to triggers likely increases in shallower locations, especially on steep, convex slopes. Snow depth is below threshold in many areas below treeline.