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Observation: Cutler Ridge

Observation Date
12/27/2020
Observer Name
Derek DeBruin
Region
Ogden » Ben Lomond » Cutler Ridge
Location Name or Route
Ben Lomond, Cutler Ridge
Weather
Weather Comments
18F at the trailhead ca. 0800am. Felt like mid teens F for much of the morning, particularly in the shade and above 8000ft. Skies were mostly clear and sunny, with a bit of cloud dropping onto the saddle, though the summit and headwall remained unobstructed. Winds were calm to light.
Snow Characteristics
New Snow Depth
3"
Snow Surface Conditions
Powder
Snow Characteristics Comments
Picked up 3 to 4 inches of new snow. While this was certainly not enough to completely fill in everything, it did soften things up and smooth things out in a few spots. Good dust on crust riding to be had with some reverse engineering of the preexisting snow surface.
New snow was small grain graupel and rime forms at lower elevation, transitioning to rime forms plus stellars with increasing altitude. Initially this looked like surface hoar, but upon closer inspection (and thinking through the snowfall amounts and recent weather) it was sparkling stellars mixed into the top of the rime forms/graupel.
Red Flags
Red Flags
Collapsing
Poor Snowpack Structure
Red Flags Comments
Experienced 4 separate small collapses on NE to NW aspects starting at 7800ft up to 8500ft (high as I went; wouldn't be surprised to find more higher). These were more or less localized to the zone immediately around my skis and did not propagate farther. No cracking associated with the collapsing. Snowpack structure is still poor. About 50cm to 70cm snow on the ground in the low to mid elevations respectively (at least where there *is* snow at low elevations). Crust-facet sandwiches are still present, with crusts in varying states of firmness and decomposition. Basal facets are growing, some perhaps 2mm in size now, forming striations and the beginning of the cups characteristic of depth hoar. However, at low elevations these basal facets were also a bit damp.
Comments
Dug in a few spots, pictured here NW at 7900ft. 65cm total snow with 8cm of F hard new snow on top and 4F just below, sitting on the crust facet sandwich visible in the photo. Three things to note in this pit:
1. ECTX (no propagation).
2. When excavating the side of the ECT column, I typically do a CT or shovel shear. When I put my shovel in for the shovel shear today, the upper 4F slab fell off immediately.
3. When excavating the other side of my ECT, I often saw out a pie wedge. The upper slab fell off immediately when I put my saw into the snow to cut the wedge.
Coupled with collapsing but no cracking mentioned above, it seems we have poor structure suitable for collapse, but it's perhaps harder to find the stored energy for propagation. Tricky stuff.
If you starred as the international person of mystery in a spy thriller, the (hopefully) incoming powder in the next few days sitting on a steep slope is the seductive love interest, just waiting to double cross you and try to kill you at the end. Don't fall for it.
It will be interesting to see how much water we get in the next day or two and what effect the new load has on the current snow structure.
We've been playing the entrenchment game for more or less the entire season so far, and that doesn't look to be changing anytime soon. (If entrenchment is a new term, check out strategic mindset in Roger Atkins paper "Yin, Yang, and You," free with a google search). But when uncertainty grows, so, too, must the margins for hazard management. Skinning up into the cloud of uncertainty around noon, I didn't have the wherewithal to see through it clearly and turned around in search of lower angle terrain.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable