Observation: Primrose Cirque

A small correction to the snow profile Shovel Shear Test result, the STE was at 30cm, not 38cm, on top of the first melt-freeze crust that is 38cm down from the snow surface.

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I began my tour at 8:45. Ran into Chris from UDOT Avalanche Safety and I saw a UAC truck on the exit... mostly people doing observations today from Aspen Grove :)

Weather was great! Calm and clear, a nice break from valley inversion.

Surface hoar (size .5-2.5cm) was prevalent from the trailhead (6800') up to approx. 8200' in the shady aspects/in the shadow of Elk Point. But this was well below the top of shrubs as the snowpack isn't more than 6-8 inches deep until you get above 8000' on shady aspects.

There was similar natural avalanche activity during the storm 10/23 as reported yesterday in Mineral Fork. The start zone below the cliff band was approx. 9200'. It looks like it slid within the new snow (possibly new snow/old snow interface) and received a few inches on top. It ran a few hundred feet. A very normal occurrence in Primrose Cirque. See photo 1. SS-N-R1-D1-S

With the upcoming storm, I'm interested how much more the first 1-1.5+ foot of snow (snow surface down) will further facet on top of a crust. In between the two crusts shown in the snow profile, is an inch or so of facets. The stout second crust sits on top of a few inches of facets, and a breakable faceted crust the last inch or so of the snowpack to ground.

Summary: I will be cautious in this area if the storms deliver this weekend. There are plenty of decomposing particles that are faceting that sit atop 2 melt-freeze crusts, making for a wonderful bed surface for an avalanche. ECTs and other tests will be essential before stepping out into avalanche terrain in the Provo area mountains when above approx. 8000'.

Photos (apologies for the vertical photos, they were for our social media posts)

Photo 1: recent natural avalanches

Photo 2: surface hoar

Photo 3: snowpit

Photo 4: Primrose Cirque

Photo 5: Primrose Cirque from the snowpit