Observation: Gold Basin

Observation Date
1/26/2016
Observer Name
Dave Garcia
Region
Moab » Gold Basin
Location Name or Route
Laurel Highway to Gold Basin
Weather
Sky
Clear
Wind Direction
North
Wind Speed
Light
Weather Comments
Beautiful sunny day in the mountains. Winds were mostly light, moderate gusts on ridge tops. Plumes of snow could be seen blowing off higher peaks.
Snow Characteristics
New Snow Depth
6"
New Snow Density
Low
Snow Surface Conditions
Powder
Snow Characteristics Comments
Six inches of light density powder that fell Sunday afternoon and evening. New snow is slightly more cohesive today than it was yesterday. Sluffs were observed on all aspects on slopes steeper than maybe 40 degrees that also contained cliffs and rock bands. These sluffs ran sunday night and monday morning.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Same
Problem #1 Comments
Dug a pit on a north aspect at mid elevation. About 20cm below the snow surface there is a weak interface between the snow that fell last week (I think it was tuesday and wednesday) and the old snow beneath it. A good amount of graupel fell during last weeks storm. I believe the graupel is the reason for the weak interface I'm seeing today. More on this below...
Snow Profile
Aspect
North
Elevation
10,300'
Slope Angle
35°
Comments
This profile is at mid elevation and north facing 35 degrees. I did not dig to the ground, I dug to a depth of 112cm. When I first dug this pit I started with a quick hand hardness test that shows a completely right side up snowpack. This is not what I expected to see after finding soft slabs on top of graupel at upper elevations both last thursday and yesterday. After seeing this I didn't think I would be spending much time in this pit at all since it looks very stable. I decided to bang on it with a compression test anyway. I was able to get a failure at 90cm (20cm below the snow surface). This failed on CT7 Q2. I found this interesting because this interface was initially hard to detect upon my first inspection of the pit wall. This is a very small amount of graupel compared to what I saw at upper elevations yesterday and last thursday. The snow that pulled out contained small amounts of graupel particles and also rimed crystals. I believe the weak interface exists here because of a poor bond (due to graupel) between last week's storm snow and the old snow below it. I tested this layer for propagation with an ECT and got no results. One must also consider what is above this weak interface, which is about 22cm of snow about half of which is very light density new snow. The 4F snow below the new snow is somewhat cohesive, but I don't see it running as a slab on top of the next layer of 4F snow that starts at the 90cm mark in my pit. Furthermore, I ski cut, and actively skied this same aspect and elevation on angles approaching 40 degrees and got no activity. Bottom line is I am not considering the results of my compression test to really be a red flag. And if you look at the big picture of this pit, the snowpack is very right side up and looking good.
Before traveling on north facing terrain I made two laps on steep, sun exposed west facing terrain. Cold temperatures have kept this snow light and dry despite lots of sun exposure. I'm thinking this will be good for perhaps one more day. A quick and dirty hand pit on this aspect shows the new snow bonding well. Travel today was on upper elevation south and west, and mid elevation north aspects. In these places the skiing is great, and things are looking relatively stable. Based on previous days obs, I'm still going with moderate at high elevation North through East.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate