Surface hoar before the storm

Out with the Patrol Fund Recreational Level 2 avalanche class near Hellroaring Peak in the southern Whitefish Range today.

• We observed no obvious signs of instability (no cracking, collapsing, or recent avalanche activity).
• We dug multiple snowpits on N and S aspects. On an open N facing slope at 6600 ft. that is protected from the wind we found two well preserved layers of buried surface hoar approximately 35 and 40 cm from the snow surface (see two prominent stripes in snowpit wall in image). We observed fracture propagation in our large column stability tests in the buried surface hoar layer at 40 cm. This layer fractured and fully propagated with hard force in our Extended Column Test (ECTP22) and twice in our Propagation Saw Tests (PST 30/100 End at 40 cm down). 
• The lower layer of surface hoar (40 cm from sfc) wasn't as well preserved in another pit just 100 feet away on the same aspect but with a bit more exposure to the wind. No fracture propagation observed in stability tests in this pit.
• Sunny aspects harbored a breakable sun crust at the surface that made for less than ideal skiing on those aspects.