Moderate - Timing or intensity of solar radiation is uncertain
WEDNESDAY NIGHT - Cloudy with clear periods and isolated flurries, up to 5 cm / west wind, 10-15 km/h / alpine low temperature -6 C / freezing level 1000 m THURSDAY - Cloudy with sunny periods and isolated flurries, trace to 5 cm / southwest wind, 10-15 km/h / alpine high temperature -4 C / freezing level 1900 mFRIDAY - Cloudy with scattered flurries, 5-10 cm / north wind, 10-25 km/h / alpine high temperature -3 C / freezing level 1800 mSATURDAY - Cloudy with scattered flurries, trace to 5 cm / southwest winds, 15-35 km/h / alpine high temperature -1C / freezing level 1900 m
On Sunday, small (size 1-1.5) wind slabs were reactive to skiers, generally around ridge crests and steep, convex terrain above 2200 m. The most reactive deposits were in immediate lee features, including a size 2 wind slab avalanche remotely triggered from a rocky saddle 10 m away. Overnight Sunday and into Monday, a natural avalanche cycle to size 2 occurred on the western side of the Purcells Forecast region. Storm slab avalanches to size 2, with crowns 20-50 cm deep were observed in alpine terrain on all aspects. On Tuesday, skiers were able to trigger slabs up to size 1.5 in steep, gully features as low as 2200m. Explosives produced avalanches to size 2 and a helicopter remotely triggered a size 1.5 avalanche from 200 m away, these avalanches all started in steep, alpine terrain above 2400 m, mostly on northerly aspects.
Recent storm snow sits on a melt-freeze crust on all aspects except for north slopes above 2100 m, snow remains dry. Southwest winds developed wind slabs around ridges and exposed treeline features and into the alpine. Below 1200 m, snow is disappearing rapidly.The base of the snowpack is composed of sugary faceted snow. The likelihood of triggering an avalanche on this layer is lower during colder periods and elevated during intense warming.