Purcells

Watch for fresh wind slab formation if you notice the wind pick up. Check out the latest Forecasters' Blog for tips on managing the persistent slab problem in this region.

Friday night: Clear. Light northwest wind. Alpine temperature around -25 C.

Saturday: A mix of sun and cloud. Moderate northwest to southwest wind. Alpine high around -18 C.

Sunday: Increasing cloud with flurries starting, up to 5 cm. Strong southwest wind. High of -13 C.

Monday: 5-10 cm new snow. Strong southwest wind. High of -10 C.

On Wednesday and Thursday, thin size 1 wind slabs were triggered by explosives and cornice failures near Golden.

We've had consistent reports of persistent slab avalanches on reloaded bed surface crusts from the Invermere area this month. On Thursday, a size 1 was triggered remotely by bootpacking on a thin northeast aspect in the alpine. Explosive control work on December 26th produced large avalanches (size 2) on the crust found 40-70 cm deep.

Recent winds have created wind slabs on a variety of aspects. A shallowly buried layer of weak surface hoar crystals may exist at treeline and below. 

The most notable layer of concern in the snowpack is a crust that was formed in early December and is now down 60-120 cm. Activity on this layer has been sporadic. It has generally been triggered on steep, rocky slopes, with a shallow or thin to thick snowpack.

This layer has created a low likelihood, high consequence scenario which is best managed through conservative terrain choices and disciplined backcountry travel techniques.

A late October facet/crust layer sits at the bottom of the snowpack above 1900m. 

• Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
• Recent wind has varied in direction so watch for wind slabs on all aspects.
• Be aware of the potential for large avalanches due to the presence of a persistent slab.
• Avoid shallow, rocky areas where the snowpack transitions from thick to thin.