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Observation: Sunset Peak

Observation Date
2/16/2017
Observer Name
B
Region
Salt Lake » Big Cottonwood Canyon » Sunset Peak
Location Name or Route
Snake Creek Canyon/Sunset
Weather
Sky
Overcast
Precipitation
Light Snowfall
Wind Direction
South
Wind Speed
Moderate
Weather Comments
Sustained Moderate winds predominently out of the S, with occasional periods of Strong. Wind blown and or transport was Moderate with active movement and loading occurring even in mid elevation semi protected terrain. Temperatures were moderated by mid day with the thickening cloud cover. In the morning hours the skies were Broken with periods of sunshine intense enough to begin softening up the steeper SE aspects. But, by noon the cloud cover was solid, and the softening at upper elevations ceased.
Snow Characteristics
New Snow Density
Medium
Snow Surface Conditions
Dense Loose
Faceted Loose
Wind Crust
Melt-Freeze Crust
Damp
Snow Characteristics Comments

At 1800 a squall moved through BCC with the rain/snow line at 7500. Only a trace of graupel fell at this point in time. The snow surface changed drastically in the past 48 hours. On Tuesday the new snow from the weekend was still very loose, airy and unconsolidated. Today the best riding had dense settled faceted snow that was best described as creamy and had an old tired feeling. Northerly aspects at upper elevations rode the best. The winds actually improved the riding conditions in many locations erasing old tracks and smoothing out the snow surfaces. In other areas there was significant wind damage and sculpting. And on any aspects on the lower half of the compass (including due E and W) there are now variable thicknesses of m/f crusts with facets below. The upper 10 cm continue to house NSF's. The settled height of the latest storm was 14 inches on the northerly protected aspects.

Red Flags
Red Flags
Recent Avalanches
Wind Loading
Poor Snowpack Structure
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Increasing Danger
Problem #1 Comments

Avalanches reported by other parties appeared to be the norm in the upper elevation wind loaded terrain. Cross Loading was as common as Top Loading. Skin tracks were filling in by the hour, and new one finger Wind Slabs of up to 20 cm were observed. At least the top 15 cm of the snowpack was showing signs of weakening and faceting. Any new Wind Slabs were being deposited on these weak surfaces. Forecasts for increasing winds will exacerbate this problem over the next 24 hours.

Avalanche Problem #2
Problem
Persistent Weak Layer
Trend
Increasing Danger
Problem #2 Comments

Any new loading either snowfall or winds will be falling on a very weak/loose snow surface, and it appears we will be returning to a Persistent Slab possibility on slopes with angles 35 degrees and greater.

There are still many overhanging Cornices that may get overloaded with the current winds and light snow forecast.

By the end of the day on Thursday Natural avalanches in steep upper elevation terrain may have been possible and Likely. As a result the predominant Danger for Thursday was at least Moderate. And there may have been very isolated pockets of Considerable due to the Natural issue. On Friday the Danger may once again rise to Considerable for the same reasons.

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