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Observation: Alexander Basin

Observation Date
1/18/2015
Observer Name
Toddeo
Region
Salt Lake » Mill Creek Canyon » Alexander Basin
Location Name or Route
Millcreek-Alexanders
Weather
Sky
Few
Wind Direction
Southwest
Wind Speed
Moderate
Weather Comments
Mostly moderate with some strong winds. Transport down to the mid elevations. Accumulation on skin track in between each run (west aspect). Wind seemed to lighten up in the afternoon. Warm. Enough dripping below 8000' on the approach to make it feel like rain at times. Dry snow began @8000' Exit into Millcreek was very damp, not as many roller balls as expected.
Snow Characteristics
Snow Surface Conditions
Dense Loose
Wind Crust
Melt-Freeze Crust
Damp
Snow Characteristics Comments

Snow surface above 8000 on shady aspects consists of dense loose snow and some wind crusts. Some very fined surface hoar.

Sunny aspects consist of a melt freeze crust.

All aspects damp below 8000'

Red Flags
Red Flags
Wind Loading
Cracking
Red Flags Comments
Wind loading wins today! Transport down to the mid elevations at times. Freshly formed cornices are minor but sensitive, crack a bit wider than the ski when kicking. One shooting crack in a sun crust! Cracked with minor spider webbing about 30' wide, culprit was near surface facets below the crust (see photos below) this was a 1st for me. 33 to 35 degree slope. At 1st I thought it was the most recent storm snow, but upon closer look, cracking was limited to crust only. ECTPV to ECTP1, Q1 at base of suncrust. Snow below crust was not cohesive enough to form a slab. More interesting than concerning. Happened on an east aspect in the aspen "sneak" into Toots to Boot. This gave me a chance to look at the basal layer of the most recent storm event and what might have caused the two skier triggered slides in the area. Culprit appears to be a thin layer of faceting decomposing crystals. Not really complete facets nor decomposing crystals. Hard call on the form. 1mm in size. ECTN, hard shear from behind (Q2).
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Same
Problem #1 Comments

Moderate danger for new wind slabs.

Avalanche Problem #2
Problem
Wet Snow
Problem #2 Comments

Mid to low elevations.

Comments

Photo 1: Upper snow profile in vicinity of crust crack. Crust on top, crystal card at basal faceting snow on top of sun crust, HS 120 cm in this area.

Photo 2: Crack in sun crust, macro view.

Photo 3: Crack in sun crust wide view, some spider webbing in lower right.

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