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Observation: Alta Ski Area

Observation Date
11/14/2020
Observer Name
Meisenheimer
Region
Salt Lake » Little Cottonwood Canyon » Alta Ski Area
Location Name or Route
Alta Ski Area (With Alta Ski Patrol)
Red Flags
Red Flags
Heavy Snowfall
Wind Loading
Poor Snowpack Structure
Red Flags Comments
It's hard to ignore the recent strong winds and heavy snowfall. The snow structure is upside down and is concerning; however, I did not see any cracking, collapsing, or unstable snowpit test results in my travels today. The good news, all this new snow fell on bare dirt, and we don't have any faceted grains in the snowpack, and instabilities won't linger long. This fresh snow should settle nicely, and the avalanche danger should decrease over the next few days.
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Same
Problem #1 Comments
Winds picked up on November 13th at about 9:00 am in the morning and blew from the SSW, averaging 30mph, gusting into the 60's. These winds continued for the next 13hrs hours from the southerly direction before veering to a more northerly direction for the remaining part of the storm. Since 1:00 am on November 14th, we've seen sustained winds from the west and northwest averaging in the 50's and 60's with gusts into the 90's. With all of last week's low-density powder snow to blow around, it's hard not to imagine the formation of wind slabs and wind drifted snow on many aspects at the upper elevations.
As I type this observation, the winds blow WNW 38 mph gusting 68 mph at 11,000'. I would still be very cautious of wind drifted snow at the mid and upper elevations for tomorrow. Let it settle for a day or two before testing the steeper terrain.
Avalanche Problem #2
Problem
New Snow
Problem #2 Comments
What a start to the winter!!!! New snow falling on bare dirt!!!! This setup is a dream come true. I dug four holes at the upper elevations today and found no faceted snow (weak old snow). However, I did find a snowpack structure that is set up for avalanches. To make an avalanche, we need four things:
1. Steep enough slope to slide (greater than 30° in steepness)
2. Weak layer (softer snow with stronger snow above)
3. Slab (stronger snow above softer snow)
4. Trigger (me, you, explosive, heavy snow, wind, etc.)
As seen in my snowpit, we are not out of the woods just yet. We have the right snowpack set up for avalanches. Strong snow, over weaker snow, is never good. I was very tempted to drop into an NE facing slope at 10,000' (see picture 2) today. As I drooled over how good it looked, I reminded myself - it's a long season, this new snow issue and will settle out quickly, we are in good shape for riding bigger lines, and today I don't want to get hurt if I am wrong. Oh, yeah, it's still shallow, and rocks are a concern.
Our snowpack is off to a great start for the 2020 winter season. The simple fact is that the new snow is a poor snowpack structure and shouldn't be trusted just yet. In a couple of days, this instability will settle out, and I think avalanches will be a thing of the past... At least until the next storm.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable
Coordinates