Snowpack

Observation: Big Cottonwood Canyon

Gagne/Duvernay/Johnston/KardonSalt Lake
View on map

Quick report

Red Flags
Poor Snowpack Structure
Red Flags Comment
<p>Poor snowpack structure is still evident, but we are definitely trending in the right direction.</p>

Snowpack

Instability Comment
<p>Field work the past two days involved using my probe quite a bit to measure snow depths where facets are present. (W/N/E aspects &gt; ~8,500') In almost every place I looked today (and <a href="https://utahavalanchecenter.org/observation/64984">Mineral Fork on Saturday</a>) the slab on top of the facets is 1-2m thick and goes from 4F down to 1F to Pencil hard, indicating a very strong slab on top of the faceted layer.</p> <p> </p> <p>We did get an ECTP30 today on an East aspect at 9,600', failing down 120 cms on the facets, and this indicates that if you were able to get a collapse and fracture in the faceted layer, the avalanche could propagate very widely and deep. On the slope we were testing the fracture would have been 120 cms / 4' deep.</p> <p> </p> <p>But the facets are gaining strength where I have been looking the past two days, moving from what had been very dry/weak F-hardness towards 4F hardness. They are also becoming damp as the temperature gradient that caused the faceting is no longer present.</p> <p> </p> <p>With such a strong slab on top and the facets gaining strength and adjusting to the load on top, we are probably very close to this PWL problem becoming dormant. (<em>Dormancy</em> means the problem still exists (didn't go away) and may become reactive once again with a load of new snow or wind-blown snow on top.) </p>

Friday night/Saturday morning 5-10 cms of storm snow weakened quite a bit and already turning to facets at the surface. Solar aspects were  damp by mid-day and likely steeper southerly faces will be crusted for Monday.

 

The snow surface turning to near-surface facets (NSF) This *may* become our next weak layer ......