Professional Observation

Observation Details

Signs of Unstable Snow

I toured from the top of June mountain today up to the top of the negatives and back into the resort. I was hoping to get an idea for localized snow totals and to gauge the impact of the recent shift to more northerly winds.

New snow totals in this area range from 1-4” with some deposition zones holding closer to 6” and some wind deposits over 24” in depth.

Areas of reactive wind slabs were observed above treeline today on several aspects. Most notably I found deposits up to 2’+ in-depth immediately adjacent to the ridgeline on an ESE aspect at 11,000’off the shoulder of San Juaquin mountain. These deposits were 1finger over fist in density and they were reactive to my weight. However, I did not observe any deposits of concerning size on my tour today. While these panels were all relatively small in size, they were certainly large enough to take me off my feet or cause a nasty fall.

I also observed some areas of thin wind slab on the sidewall of a NE facing gully feature in the negatives. These deposits were only 2-3” thick at most but the conditions were pretty slick Dust on the crust, and it would not have taken much for these to kick me off balance here. Also, worth noting that the old surface here is very hard and slick windboard making for a good bed surface.

I observed localized cracking in several areas near and above treeline where recent winds have deposited snow. And surface clues support the redistribution of snow resulting from both the SW winds during the storm as well as the more recent north winds.

Some flagging was observed on the high peaks today along the 395 corridor as well as off the top of the negatives. Higher elevation northerly start zones are mostly stripped back to old snow surfaces at this point. I suspect Wind deposits on northerly terrain will be more isolated in distribution.

No signs of excessive warming today however I did note the presence of a thin melt-freeze crust on the surface in areas near and below treeline that saw direct sun input yesterday.

Ski quality varied greatly depending on elevation and aspect today. Sheltered terrain at lower elevations was pretty predictable ranging from dust on crust to soft pow turns. Exposed areas near and above treeline have a more sporadic distribution of new snow. There are plenty of areas of old snow surface-exposed providing a very hard and slick experience. Ski crampons were a good idea today.

The upper fourth or so of the negatives was stripped back to the old surface of hard and slick windboard and further down I found fairly stiff powder turns over crust. The surface is being actively compressed by the north winds and I would suspect a new layer of breakable windboard soon.