Observation: Moab

Observation Date
12/21/2019
Observer Name
T. Matthews D. Garcia
Region
Moab
Location Name or Route
Gold Basin Exxon's Folly
Weather
Sky
Overcast
Wind Direction
South
Wind Speed
Calm
Weather Comments
Broken skies (BKN) turning to overcast (OVC) by early afternoon. Temps were warm and with no wind or breeze in the terrain we looked at toda it felt quite warm at times. Pulling temps from Gold Basin and Pre Laurel confirmed that it was a warm one. Noted south winds after looking at the Pre Laurel WX station wind data. SSW winds becoming due S at approx. 1100.
Snow Characteristics
Snow Surface Conditions
Dense Loose
Faceted Loose
Melt-Freeze Crust
Snow Characteristics Comments
Solar aspects have taken a beating. 3 weeks now without a solid refresh has hammered the surface on all aspects that face the sun. You'll find faceted loose snow on the sheltered north facing slopes in terrain above 9,500 feet. In our travels today on due north slopes that have not felt the wind you could feel the facets underneath your skis.
Red Flags
Red Flags
Poor Snowpack Structure
Red Flags Comments
The snowpack is losing strength. 3 weeks of high pressure have created some layers in the pack that will become problematic once a slab has been added on top of them. Did not observe any wind in our travels today as we stayed well below the treeline. I heard it a couple of times well above us. Pulling wind speeds and directions from the Pre Laurel WX station confirms that the wind speeds were high enough to transport snow. I just think there's not much left to transport. Did not notice any plumes of snow blowing off any of the high alpine peaks.
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Decreasing Danger
Problem #1 Comments
Didn't get in to the terrain today where this problem type could live. I suspect there's so little snow available for transport now that we will have to wait until the mountains receive more new snow for this problem type to increase in danger. Pulled winds speeds from the remote WX stations. Fast enough to transport snow I just didn't see any plumes blowing off of the high alpine peaks. Perhaps in lower elevations that tend to be more sheltered and are holding softer snow you could see some cross loading events take place. If you managed to find a wind slab that was sensitive enough to fail I would think it would be quite shallow. Not deep enough to bury you, but in the wrong terrain it could send you off a rock, or bang you in to some trees.
Avalanche Problem #2
Problem
Persistent Weak Layer
Trend
Decreasing Danger
Problem #2 Comments
This I am sure will echo the past few observations I have read. The snowpack is loosing strength. I have not had my eyes in a pit in the La Sals for a couple weeks, so it was time to see what's likely going to be most problematic once winter decides to return. Hopefully starting Monday with a better chance of snow on Tuesday and Wednesday. An X-Mas special would be nice. Dave and I pulled our shovels out on an 318 degree NNW slope at 9,904 feet. Near the toe of Exxon's Folly historic trim line. We found an average depth in our pit of 69 cm. 2 layers stood out to me the most. The first being roughly 14 cm down from the surface. A 2 cm thick F hard layer off small grain facets. They measured .2 mm - .5 mm and were reactive in Compression Tests. Test one CTE SC Q1 failing on the 5th tap. 2nd test CTE SC Q1 failing on the 3rd tap. We then set up an ECT. I was thinking we would not see propagation. Scored that one as an ECTX. The F hardness snow above that weak layer was simply not strong enough to propagate across that column. This layer could be the problem when we add a slab on top.
The 2nd layer of concern was another layer of facets closer to the ground with a 4F to 1F 15 cm thick slab sitting on top of them. This weak layer is 9 cm thick containing .5 mm - 1 mm facets with a bit of rounding present. This layer is on a 5 cm thick P+ crust that's sitting on the ground. After our CT's I put then shovel deeper in to the snowpack and continued the CT. Could not get this layer to fail. During our ECT after about 20 taps the side I was hitting was blown out. I wailed on the last ten to see if I could get the faceted layer closer to the ground to fail and propagate. I could not. Still seams like the basal facets are non reactive.
Danger trending downward in my opinion until we add more weight and slab to the snowpack.
Snow Profile
Aspect
Northwest
Elevation
9,900'
Slope Angle
16°
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Low
Coordinates