Purcells

Conditions are tricky with a slowly increasing load over multiple weak layers in the snowpack. Take a conservative approach to your terrain choices.

Moderate - Intensity of incoming weather systems is uncertain

Sunday: 5-10 cm snow. Light south-westerly winds. Alpine temperature near -5.Monday: 5-10 cm snow. Moderate to strong south-westerly winds. Alpine temperature near -3.Tuesday: 5-10 cm snow. Light to moderate south-westerly winds. Alpine temperature near -5. More information can be found in the Mountain Weather Forecast.

On Friday we received reports of several explosives-triggered persistent slab avalanches  (to Size 3), primarily on northerly aspects above 2200m, running on the Jan 5th surface hoar layer. With consistent but incremental loading over the next three days, human triggering will remain likely and avalanches could be surprisingly large due to the structure of the snowpack.

The current snowpack is complex, with three active weak layers that we are monitoring.60-100 cm recent storm snow overlies a crust and/or surface hoar layer (from mid-January). The crust is reportedly widespread, except for possibly at high elevations on north aspects. The surface hoar is 10 to 30 mm in size, at all elevation bands. The recent snow fell with strong south winds, producing wind slabs and cornices in lee features. Deeper in the snowpack, a persistent weak layer known as the early-January layer is present at all elevation bands, and composed of surface hoar on sheltered slopes and sun crust on steep solar aspects. Recent snowpack tests have shown sudden fracture characters with moderate loads and high propagation potential, as well as other signs of instability such as whumpfs, cracking and avalanches. Another persistent weak layer that was buried mid-December is 60 to 100 cm deep and consists of a facet/surface hoar/crust combination. It is most problematic at and below tree line.A rain crust buried in November is 100 to 150 cm deep and is likely dormant for the time being.