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Observation: Salt Lake

Observation Date
3/5/2018
Observer Name
B
Region
Salt Lake
Location Name or Route
Brighton Perimeter
Weather
Sky
Scattered
Precipitation
Light Snowfall
Wind Direction
West
Wind Speed
Moderate
Weather Comments
Light snow early in the day (Sminus1) with skies clearing at 8000 feet in Silverfork, but in the Brighton Perimeter high thin cloud cover and scattered. Temperatures remained true winter like and appeared to never get above the low teens at 9000 feet and above. W to WSW winds were moderate in the alpine with moderate wind blown and or transport.
Snow Characteristics
New Snow Depth
5"
New Snow Density
Medium
Snow Surface Conditions
Powder
Dense Loose
Wind Crust
Snow Characteristics Comments

Riding conditions became much more stiff and settled due to the winds over the past 12 hours. In the most exposed areas there were 4 finger to 1 finger wind slabs up to 10 inches deep scattered across the terrain. In areas out of the the direct WSW winds the riding was dense and thick/creamy; and the most protected areas the riding remained soft and buoyant.

Red Flags
Red Flags
Recent Avalanches
Wind Loading
Cracking
Poor Snowpack Structure
Red Flags Comments
Poor snowpack structure continues to inhabit the outlying areas beyond the Alta and Brighton Perimeter and observations of persistent slab avalanches detail a snowpack waiting for a trigger and or additional loading. Two wind slab avalanches were observed on different aspects, and one appeared to be human triggered. The human triggered avalanche was at least 40 degrees in steepness, 60 feet wide and ran 120 feet. This slide was in between 1000 Turn Gully and Figure 8 on a ENE aspect. The other slide was a natural located on a southerly facing ribbed terrain feature on the Highway to Heaven. It appeared to be at least 75 feet wide and ran 150 feet. Both appeared to be in the 12 to 16 inch range. See photos below, and they aren't that great due to poor lighting.
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Same
Problem #1 Comments

See above for wind loading details, and with the winds forecast to remain strong enough to continue creating larger and new wind slabs, the problem may still be an issue in the exposed alpine on NE, E and SE aspects. By the end of the day on Tuesday, this problem should show signs of decreasing.

Numerous loose dry avalanches were observed on various very steep aspects, and some were entraining enough material to create problems if someone was in consequential terrain.

Avalanche Problem #2
Problem
Persistent Weak Layer
Trend
Same
Problem #2 Comments

See above with regard to the concerns related to the outlying areas. As other observations report, the Mill Creek drainage and surrounding areas appears to have the most suspect snowpack conditions in the Tri-Canyons.

Danger today appeared to be a very isolated Considerable due to the limited natural wind slab activity observed, and cited above. Speculation would have other similar activity as a result of wind loading and the abundant snow available for transport. Out of the wind loaded areas the danger appeared to be moderate for lingering storm slab potential. Hasty pits continued to indicate a sensitive/reactive layer 5 cm up from the old snow/new snow interface of this weekends latest event.

The danger for Tuesday may remain Considerable for the only reason that the sun and ambient temperatures will help initiate the first wet loose avalanche occurrence in this past weekends snow event. Besides this problem, the danger appears to be moderate for all the same problems cited above.

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