Observation: Alta Periphery

Observation Date
12/29/2017
Observer Name
CBrown

Region:

Location Name or Route
Alta/Brighton Periphery
Weather
Sky
Clear
Wind Direction
Northwest
Wind Speed
Light
Weather Comments
Pretty warm and sunny out there today, doesn't feel like Dec/Jan. Light winds for the most part with more in the moderate range on ridgelines. Temps felt like above freezing most of the day.
Snow Characteristics
Snow Surface Conditions
Powder
Wind Crust
Melt-Freeze Crust
Snow Characteristics Comments

Saw quite a variety of snow surfaces out there.  It seems as though the winds have gotten on the snow since Tues/Wednesday.  Quite a bit of wind board, wind crust and other wind affected snow.  Still some soft settled powder that is skiing quite nice on sheltered aspects, and even on low angle upper elevation southerly aspects.  There was also M-F crusts on southerlies that had a little more of a angle to them.  All in all it seems as though are snow quality/riding conditions are deteriorating, which is quite depressing looking at our forecast.

Red Flags
Red Flags
Recent Avalanches
Wind Loading
Cracking
Poor Snowpack Structure
Red Flags Comments
Again, seing quite a few of those red flags during our travel today. Not seeing any very recent avalanches and espically not any new natural avalanches in our travels. For me the big take away is the snowpack structure. As docile as the mountians appeared to me today knowing what is lurking under the surface kept my decisions conservative.
Avalanche Problem #1
Type
Persistent Slab
Trend
Same
Problem #1 Comments

Repeat of the last week or so, I think this is the main problem.  Even as we approach almost a week out from our last storm, this problem is still lingering.  The persistent slab problem is, well, persistent by nature, and while last year we would see things settle out this problem isn't going anywhere fast.  What I perceived as more of a moderate hazard today does not mean it's good to go.  While things may seem to be settling out, our instabilities and weak layers are still there, and a low probability but unpredictable and high consequence outcome is something worth avoiding.

Avalanche Problem #2
Type
Wind Slab
Trend
Decreasing Danger
Problem #2 Comments

Still seeing those hard slab wind slabs along ridge lines.  Knowing what is under these hard slabs makes me thin this is still an issue and could lead to a larger avalanche if it steps down or activates the PS problem.

Comments

We dug three pits today below Wolverine Bowl in the chutes areas leading to Lake Mary.  All these pits were between 9,900' and 10,00'.  We dug on NNW, NE, and NW and performed an ECT in each pit and saw three ECTX.  The depth of the snow pack was 160 cm on NNW pit where upon wailing on the 31st hit had full propagation on the NSF below the slab which was made up of the three storms going back to last Wednesday.  When digging on the adjacent NE and NW aspects with a shallower pack (100-120cm) we expected to get a result on this layer but again nothing. The NE and NW pit we performed a CTN as well.  I believe this is showing a false sense of stability and my takeaway is that although stubborn in many places the structure is out there to produce a large, unmanageable avalanche that is hard to predict and deserves some respect.

Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable
Snow Profile Coordinates