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Observation: East Bowl

Observation Date
2/19/2017
Observer Name
Greg Gagne
Region
Salt Lake » Big Cottonwood Canyon » Silver Fork » East Bowl
Location Name or Route
East Bowl Silver Fork
Weather
Sky
Obscured
Precipitation
Heavy Snowfall
Wind Direction
West
Wind Speed
Moderate
Weather Comments
Swirling winds, but generally out of the west. Periods of heavy snowfall late morning.
Snow Characteristics
New Snow Depth
12"
New Snow Density
Medium
Snow Surface Conditions
Powder
Wind Crust
Snow Characteristics Comments

Storm totals since Friday are now totaling 30-45 cms (12-18") including 1" of water during the day on Sunday.

Red Flags
Red Flags
Recent Avalanches
Heavy Snowfall
Wind Loading
Cracking
Red Flags Comments
Biggest red flags were easily triggered avalanching as well as what appeared to be a natural avalanche.
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Increasing Danger
Problem #1 Comments

This problem also includes storm slab. Very easy to provoke avalanches today in storm snow, especially where wind-loaded. With winds forecasted to remain in the moderate category (with stronger gusts at the upper elevations) fresh wind slabs are likely to continue to form, so an increasing danger. Storm slab instabilities will settle out rapidly, and not likely a concern for Monday.

Comments

[Sorry - no photos or video. Super flat light with very poor visibility]

Spent the morning in East Bowl of Silver Fork. Arriving at East Bowl pass at 800 am we were finding more snow and wind than expected. Ski cuts on any steep slope - especially on those that were wind loaded - easily produced class 1 slides running within storm snow. Finding two different density-changes in layers within storm snow today - both in top 30 cms (12")

These slides were running 50' - 150'.

On larger slopes we were able to trigger at least one class 2 slide that ran at least 250'. Another party triggered a class 2 that likely ran over 300' with a sizable debris pile.

The hazard spiked to Considerable by late morning with high precipitation rates as well as wind loading. Lots of cracking within the storm snow, as well as debris from what appeared to be a recent natural avalanche running within storm snow.

For Monday, any storm slab instabilities should have settled out. Wind may be enough of a concern at the upper elevations for Monday.

(This was a text I shared with Trent later this afternoon: "I was really surprised how quickly the old faceted layer became more dense and not as loose and cohesion less. I thought for sure new snow would bond poorly, but overall it has bonded pretty well. I also thought Thursday’s wind drifts would have remained sensitive at least through Friday, given that they were sitting on top of such weak, faceted snow. But it seemed they stabilized somewhat by Friday, and by Saturday they were not reactive at all. Today seemed to have weaknesses within the storm snow only. Will be interested in what others are finding.")

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