Cougars, Crack, & Hoar

Based on forecasted avalanche problems for today, one goal of our sidecountry tour from WMR was to observe ridges and slopes affected by wind transport, as well as the current snow surface conditions.

• We were attentive to the distribution and preservation of surface hoar, after cold overnight temperatures and clear nights.
• Initially, we observed surface hoar on the shaded aspects of the leeward side of Skook ridge. 
• For the majority of the day, we did not observe obvious signs of snow instabilities. We observed a diverse range of tracks in the snow, with one report of an unconfirmed set of cougar tracks.
• We did see and feel the differences between shaded aspects and those affected by solar radiation.  As expected, the slopes that received sustained sunshine in the previous days, were crusty with a melt-freeze layer.  In contrast, shaded slopes afforded good skiing in soft snow.
• It appeared that light to moderate southwest winds and partly cloudy skies kept the snow surface from rapid warming and wet snow instabilities.
• At around 230pm, when skinning back up to Skook ridge, we saw blowing snow along the ridgeline.  This led to further investigation into the potential for wind slabs on a layer of buried surface hoar.
• Yep, we found it (see photo A).  Consequently, we jumped on small test slopes and cornices, to gauge how reactive they were and as shown in the photo B & C, we had good results in propagating a wind slab that slid on the buried weak layer of surface hoar.
• Additionally, we observed signs, such as cracking from our skis while traveling on this ridge of wind affected snow (see photo D).