Observation: Bonner Ridge

Observation Date
1/7/2019
Observer Name
Joey Dempster
Region
Provo » Snake Creek » Bonner Ridge
Location Name or Route
Bonner Ridge, Snake Creek, Midway
Weather
Sky
Obscured
Precipitation
Moderate Snowfall
Wind Direction
West
Wind Speed
Strong
Weather Comments
Snowing and blowing between 7 and 9am when I was out.
Snow Characteristics
New Snow Depth
2'
New Snow Density
Medium
Snow Surface Conditions
Powder
Dense Loose
Snow Characteristics Comments
2' depth is for the Sat/Sun/Mon total. It's hard to tell exactly where the boundary is between the first and second systems. In any case the interface between the two does not appear to be a critical discontinuity. Overall the new snow was medium density. However, there were a few palpable density changes that could be felt when pole probing. Only the top layer was reactive, however. All lower density shifts seemed to be adhering to one another.
Red Flags
Red Flags
Heavy Snowfall
Cracking
Red Flags Comments
1. Lots of new water weight on a snow surface that was subjected to several very cold nights and developed some facets. 2. Top several inches of snow this morning was cracking easily and was reactive in tests.
Avalanche Problem #1
Problem
New Snow
Problem #1 Comments
I had just enough time to get to 9000 feet this morning for a look around. In non wind affected terrain, there was an obvious density inversion at about 5-6 inches down in the new snow. This top layer was cracking easily on rollovers and switchback corners. An ECT on a 33 degree sheltered slope well down off the ridge produced a partial fracture (ECTN11) at 11. It did not run cleanly, but the fracture did propagate.
The ECT result was a bit worrisome, but it was shallow. If more snow piled up on it during the day, if that layer was deeper up higher, or if wind transported snow loaded on top of it, it could easily fail and produce slab avalanches. Underneath that, the new snow was well behaved, at least at the mid elevation sheltered terrain that I observed. I felt comfortable on the 30 degree slope, but would not have skied anything steeper today. I feel like this particular weakness will heal quickly. On Tuesday morning, I would expect to see less cracking in the top of the snowpack, but I would be on the lookout for it, particularly since it could be buried more deeply after a few more hours of snowfall.
I did not observe any weakness below this in the new snow.
Winds were obviously high above so I would assume that the avalanche hazard was higher up above on the ridges, and will remain so tomorrow, but 30 degree sheltered slopes should have a hazard rating at least 1 step lower than the ridges tomorrow. (i.e. if considerable, these slopes will have a moderate hazard)
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable
Coordinates