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Observation: Snowbird periphery

Observation Date
4/9/2017
Observer Name
B
Region
Salt Lake » Little Cottonwood Canyon » Snowbird periphery
Location Name or Route
Snowbird Periphery
Weather
Sky
Obscured
Precipitation
Light Snowfall
Wind Direction
Northwest
Wind Speed
Light
Weather Comments
Obscurred skies and light snowfall until early afternoon. NW winds were in the high end of the Light category and Light Wind Blown and or Transport observed. Skies cleared to Few in the mid to late afternoon. Temperatures at the 8000 feet in the afternoon rose rapidly.
Snow Characteristics
New Snow Depth
18"
New Snow Density
Low
Snow Surface Conditions
Powder
Wind Crust
Damp
Snow Characteristics Comments

Right side up storm with the last half of the event depositing light density snow. Buoyant riding in bottomless powder in areas unaffected by the wind. Upper Elevation exposed terrain had wind whales and scouring. All slopes with angles < 25 degrees ending up becoming damp in the mid to late afternoon.

Red Flags
Red Flags
Recent Avalanches
Wind Loading
Poor Snowpack Structure
Red Flags Comments
Reports of wind aided slabs appear to indicate that the poor snowpack structure observed at the new snow interface involving a graupel layer may still be reactive in steep terrain in the upper elevations. Snowpit tests at 9900 feet on wind protected moderate angled NE and ENE aspects had CTM Q2 scores indicating the possibility that for this weakness may linger into Monday. Also observed was a density break weakness that was indicated in positive Tilt Tests and CTE Q2 scores. This weakness appeared to be light density layer that was 12 tp 15 cm down; and most likely it will settle out significantly by Monday. That said, numerous Loose Snow Dry Avalanches/Sluffs were observed in very steep upper elevation terrain with aspects ranging from E to W. Also of note the Y Coular and the chute just down canyon from it appeared to have natural activity that reflected this weakness as a reactive layer. Of note, the Wind Slab reported in Cardiff may have also had this above cited density break as a reactive weak layer.
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Decreasing Danger
Problem #1 Comments

Upper elevation Wind Slabs appear to be the number one avalanche problem of concern for Sunday and most likely they will be a possibly player on Monday. All upper elevation aspects that appear to have observable pockets of wind loading and slabs may be suspect for another day.

Avalanche Problem #2
Problem
Wet Snow
Problem #2 Comments

Loose Wet activity was observed in the afternoon hours on steep southerly facing slopes; and with the escalating daytime highs forecast for Monday this problem should be much more active; and the E and W aspects should become involved as a result.

Along with this, very steep northerly facing slopes may continue to have Loose Dry Avalanche potential, and if ridden with caution these should be mostly manageable.

It appeared that by mid morning the Avalanche Danger was Moderate for the Wind Slab and Storm related Dry Loose issues. The Wet Loose Naturals appeared to indicate a rising Danger rating closer to Considerable, yet this problem appeared to be very isolated with the cooler temperatures on Sunday. For Monday, once these Wet Loose Naturals become active and more widespread a Considerable rating may be applicable.

Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Considerable