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Observation Date
2/12/2021
Observer Name
E
Region
Salt Lake » Big Cottonwood Canyon » Brighton Perimeter » Snake Creek
Location Name or Route
Snake Creek
Weather
Sky
Overcast
Precipitation
Moderate Snowfall
Wind Direction
Southwest
Wind Speed
Moderate
Weather Comments
Temperatures appeared to feel more like a spring storm day. Sustained Moderate to Heavy snowfall rates throughout the day with accumulations of at least 4 inches from 0900 to 1300. The WSW winds appeared to accelerate from Light to Moderate by mid morning hours with Moderate Wind Blown observed in the Upper Elevation exposed terrain.
Snow Characteristics
New Snow Depth
14"
New Snow Density
Medium
Snow Surface Conditions
Powder
Snow Characteristics Comments
Excellent riding in at least 12 inches of moderately dense snow with a slight inversion in the new snow occurring by late morning and into the early afternoon hours. The new snow from that past few days gave the riding a spongy base with the moderate densities of the new snow giving it a light creamy feeling.
Red Flags
Red Flags
Recent Avalanches
Heavy Snowfall
Wind Loading
Cracking
Poor Snowpack Structure
Red Flags Comments
Multiple Naturals and Human Triggered Storm Slab Avalanches observed: see Avalanche Observation. Soft Wind Slabs of up to 16 inches were common on the leeward ridge lines. Of Note is the potential for the Southerlies to become a problem over the next 48 hours if we receive the significant loading as predicted by the latest forecasts. There is a friable 1 inch m/f crust with small facets underneath it, and this crust was formed during the warming earlier in the week. Collapse failure may come into play once we get a more substantial load on these aspects. See photo from Avalanche Observation that depicts NSF's (and resulting failure plane) that were formed on the Northerlies during the dry period on the 8th and 9th.
Avalanche Problem #1
Problem
New Snow
Trend
Same
Problem #1 Comments
Todays Widespread Storm Slab activity appears to have elevated this as the number one problem in the areas traveled today, and if the forecast verifies on the high end this problem may continue to be an issue of concern.
Avalanche Problem #2
Problem
Persistent Weak Layer
Problem #2 Comments
See above comments, and the question remains the same: are we still dealing with potential reactivity when we get new loading on the buried PWL's? The answer is Very Likely in areas with the shallower snowpacks.
Also of concern is the forecast for the Winds to continue to remain in the Moderate range in the Mid Elevations, and Strong in the Upper Elevations at least until the early morning hours. This potential for additional loading is a not just a concern for new Wind Slab development, but also for the possibility of overloading the buried PWL's.
Considerable appeared to be the Danger Rating for today due to the Widespread Storm Slab activity, and if the forecast for tomorrow verifies on the high end this Considerable Rating may elevate to High tomorrow during any significant new loading from either New Snow and or Wind.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable