Observation: Moab

Observation Date
01/4/2017
Observer Name
Dave Garcia

Region:

Location Name or Route
Laurel Highway/Gold Basin
Weather
Sky
Overcast
Precipitation
Moderate Snowfall
Wind Direction
Southwest
Wind Speed
Strong
Weather Comments
Snowfall began around 9:15 and was intermittent throughout the day. At times it was moderate intensity. It's hard to say how much snow fell from the sky today. My guess is three to four inches. Winds were blowing hard and moving snow all around. High elevation NE aspects were being rapidly loaded today. Every now and then the gusts were from the west and this even started to cross load south facing slopes like Gold Miner's.
Snow Characteristics
New Snow Depth
4"
New Snow Density
Medium
Snow Surface Conditions
Powder
Dense Loose
Wind Crust
Snow Characteristics Comments
A trace of new snow at the Geyser Pass TH to start the day. New snow depths got deeper on the way up Laurel Highway. As mentioned, winds were quite strong so it was hard to estimate snow totals, but I think 3 to 4 inches is a good guess of what actually fell from the sky. I've posted a picture below of ski penetration in a sheltered spot as a measure of the new snow.
Red Flags
Red Flags
Heavy Snowfall
Wind Loading
Cracking
Red Flags Comments
Snowfall was moderate today, but the forecast for tonight and tomorrow is calling for more snow. This combined with today's heavy winds, which should continue into tomorrow, will lead to an increasing avalanche danger. I found isolated wind slabs today, even on the windward side of the ridge. They are fragile and were cracking at my feet as I crossed them.
Avalanche Problem #1
Type
Wind Slab
Trend
Increasing Danger
Problem #1 Comments
This storm is coming in with lots of wind, and wind slab is going to be our most obvious avalanche problem in the coming days. I mentioned isolated fragile wind slabs on the windward side of the high ridges, these will be something to watch out for since this is mainly where we ski. On the lee sides of the high ridges the wind slabs will be a lot more obvious and more widespread.
Avalanche Problem #2
Type
Persistent Slab
Trend
Same
Problem #2 Comments
The northerly facing slopes are still harboring some weak layers that we need to remain suspicious of. I dug a pit today on a 38 degree slope facing NNE around 10,000 ft. The graupel layer that I have been seeing in recent pits is becoming less and less reactive each time I see it. Upon first seeing this layer last Thursday 12/29 it was a mixture of graupel and facets. Today it is graupel and rounds, and the rounds are bonding to the graupel pellets. A shovel shear revealed this layer, but this layer did not react to a compression test. I dug to the ground and the total depth was 142 cm. The graupel layer is at 109 cm. There is another layer of concern below the graupel layer at 88.5 cm. This is a thin layer of small facets. This layer was very obvious upon digging the pit. This layer is easily visible in my photos below. It showed itself very clearly without even touching the pit wall with my hand. I performed two stability tests on this layer. The first was a compression test, and the layer failed CTM 17 Q2. The second was a propagation saw test. This is a pass/fail test for propagation, and the layer passed. Why am I concerned about this layer? Well, there is for sure a slab on top, mostly four finger and one finger snow, which makes good slab material. It's also in the top meter of our snowpack. I think right now the strength to stress ratio with this layer is about even. This was a test slope. If it had been a slope I was thinking of skiing, I probably would have skied it. This was in a somewhat sheltered spot with no wind loading. Add wind load to this mix and I probably wouldn't ski it. The continuing storm over the next two days should put a bit more stress on this layer, and we'll see what happens. I think the big picture for the next two days is going to be wind load, and new snow instabilities should we get the forecasted amount of snow, hope so!
Ski penetration showing 3 to 4 inches of new snow around noon. Snow had mostly stopped after this time.
The obvious weak layer at 88cm can be seen in the lower third of this picture. It is the dark, horizontal line across the pit wall.
Another angle on that weak layer. Here it is seen along the sidewall of my pit. The last photo is a shot of the propagation saw test. The saw is sticking out of the weak layer, and you can see the slab above. There is new snow on top and the slab is made of mostly four finger and one finger snow. The weak layer passed this test.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Considerable
Snow Profile Coordinates