Purcells

Triggering large avalanches is still a serious concern in the Purcells. We highly suggest adopting a conservative approach to route selection.

High -

SATURDAY NIGHT: Cloudy with isolated flurries along western slopes and clearing skies on eastern slopes, moderate west wind, alpine temperatures drop to -10 C.SUNDAY: Cloudy with sunny periods, light northwest wind, alpine high temperatures around -8 CMONDAY: Mix of sun and cloud, light northwest wind, alpine high temperatures around -10 C.TUESDAY: Cloudy with isolated flurries in southern parts of the region, moderate southwest wind, alpine high temperatures around -8 C.

Small wind slabs (size 1) were reported throughout the region on Saturday, as strong wind loaded lee terrain. However, given the weak nature of the snowpack, the main concern is still triggering deep persistent slab avalanches. Large and very large (size 2.5-3.5) avalanches have been reported regularly over the past few weeks (with the most recent report from Wednesday). Most activity in the past week was in south facing alpine terrain, but the problem has presented itself on all aspects over the past few weeks.Last weekend, a group of snowmobilers triggered a fatal avalanche near Invermere, also on the basal weak faceted grains. The avalanche was on a southerly aspect and ran approximately 900 to 1100 m. Two snowmobilers were caught. See here for more information.

The snowpack is weak and touchy in large portions of the Purcells, with very large avalanches being reported on a regular basis. Read the Forecaster's Blog here for a more detailed description of conditions in the Purcells.5-15 cm of new snow is burying large surface hoar crystals and/or sun crusts, which could eventually develop into a touchy problem as snow accumulates. The most suspect terrain features will be steep slopes and rolls below 2000 m (where the largest surface hoar exists) and steep south-facing slopes in the alpine (where sun crusts exist).The weak nature of the snowpack lies at depth. There is a weak layer around 80 to 120 cm deep, composed of sugary faceted grains, feathery surface hoar, and a sun crust. The base of the snowpack is also composed of weak faceted grains in many parts of the region. Humans have and will continue to be able to trigger these layers in areas where the snowpack is shallow.