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Professional Observation

Basic Information

Observation Details

Observation Date:
January 26, 2024 - January 26, 2024
Submitted:
January 27, 2024
Observer:
TAC - Charles Harrison
Zone or Region:
Taos Area
Location:
Williams Lake TH

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
None Experienced
Collapsing? 
Isolated
In agreement with the current moderate danger rating, we didn't see many obvious signs of instability like natural avalanches or large shooting cracks. However, we did get a few small collapses in the shallower spots where we traveled, and our snow pit indicated a generally weak snowpack structure: ECTP23, PST 35/150 END on the layer of facets from late December. We also found widespread depth hoar (see image), which is becoming highly developed and remains near the snow surface in shallower spots. After digging around, we noticed that the depth hoar was behind some of the collapses that we experienced.

Snow Stability

Stability Rating: 
Fair
Confidence in Rating: 
High
Stability Trend: 
Steady

Bottom Line

Today was a solid confirmation that the snowpack in our area continues to exhibit a strong-over-weak structure. The weak layers that developed over the early season months before Jan. 4th are continuing to facet and were prominent in all spots where we looked today. The slabs on top are fairly large (1-4ft) and continuing to harden, which also means that avalanches are a little bit more difficult to trigger. That being said, we did collapse the weak layers in a couple of shallower spots on the margins of slabs that we crossed or were near. Keep this last piece of information in mind as you travel around the mountains, because these trigger points are where you're most likely to trigger an avalanche and they are definitely out there.

Media

Shallow spot on the margins of a slab in NW facing terrain near treeline. HS <40cm
Depth Hoar (2-4mm) found near the ground on West facing terrain.

Advanced Information

Weather Summary

Cloud Cover:
Overcast
Temperature:
15-20
Wind:
Light , NE

Temperatures were moderate where we toured today, mostly in the high teens. The snow was falling lightly for most of the day (S1) with a few moments of slightly more intense precipitation and a little bit of graupel around 1pm. Winds were light all day with a few moderate gusts in the mix. There wasn't much active wind transport going on in our area even though it is a highly wind-affected area, and as a result we didn't see any wind slabs forming in the upper snowpack.

Snowpack Observations

We dug a profile at 11,600' on a West facing gully and got the following results:

HS 90-125cm
CT26 on 1-2mm facets (December draught layer)
ECTP 23 on the same weak layer
PST 35/150 END on the December layer

I'll also note that we found large depth hoar in this snowpit and found the location to be a good example of how the slab thickness/weak layer depth can taper rapidly over a short amount of space. Look at the photo and consider that it will likely be easier to collapse the December layer or the depth hoar on the left side of our slab versus the right.

Snow pit in a cross-loaded, West facing gulley near treeline. Note the differences in depth of the weak layers.

Avalanche Problems

The persistent slab problem is alive and well, albeit more stubborn than it was a week ago. I expect the avalanche hazard to rise if we see enough warming in the next few days, and certainly if the storm that's coming our way towards the end of next week adds a significant load to this snowpack.

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