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Observation: Mirror Lake Highway

Observation Date
12/1/2019
Observer Name
Staples, Gardner, Collings, Kynaston
Region
Uintas » Mirror Lake Highway
Location Name or Route
East of Mirror Lake Highway
Red Flags
Red Flags
Cracking
Collapsing
Red Flags Comments
Saw cracking in cut banks. Observed a collapse on the small slope where we dug our pit. It was enough to rattle small saplings and make them drop their snow.
Avalanche Problem #1
Problem
Persistent Weak Layer
Problem #1 Comments
THIS IS THE AVALANCHE PROBLEM THAT WILL KILL. It exists on upper elevation northerly facing slopes and east-facing slopes that harbored old snow before the Thanksgiving week storms. This weak layer formed over part of October and November. It will not go away for a month or two AT LEAST. We will see more avalanches on this layer.
HEADS UP: Avalanches on this layer can be triggered from flat terrain underneath steep slopes.
Snow Profile
Aspect
North
Elevation
9,600'
Slope Angle
15°
Comments
First photo below shows the pit in the profile above. The weak faceted snow (depth hoar) at the ground is about a foot thick and easy to see in the photo. It now has a soft slab on top of it that will create a large deadly avalanche.
Second photo is a close up of the sugary snow crystals near the ground. They are called facets because they have straight sides and edges. The grid on the card is 2mm.
Video
Today's Observed Danger Rating
High
Tomorrows Estimated Danger Rating
Considerable
Coordinates