Observation Date
12/21/2014
Observer Name
Toddeo
Region
Salt Lake » Park City Ridgeline
Location Name or Route
Willows to PC Ridge
Weather
Sky
Obscured
Precipitation
Heavy Snowfall
Wind Direction
Northwest
Wind Speed
Strong
Weather Comments
Nuking and puking! On and off snow brusts up to >1-2" per hour (S5). Winds were moving large amounts of snow on the PC Ridge and in some areas that are typically sheltered. Damp, felt colder than it was. Hard to face into the wind without googles.
Snow Characteristics
New Snow Depth
7"
New Snow Density
High
Snow Surface Conditions
Dense Loose
Damp
Snow Characteristics Comments

4-8" new depending on elevation. 1.5" of slop on the car at Solitude after walking all day.

Graupel, rimed stellers, pellets, needles, total mixed bag. Damp to 9500'. Wet below 9000'.

The 4" on the ski in this am was already almost impossible to isolate on north aspects, columns and EC's broke in the drier recystalized old snow surface. Didn't change during the day as snow accumulated. Columns were also difficult to isolate on south and SW aspects, generally breaking above crusts on a density inversion.

Drifting to 2' deep on and near the PC ridgeline. Some soft cracking in these areas, I imagine with time these areas will start to form shooting cracks, my guess is that slabs were not stiff enough yet,

North aspects were inverted with 6-8" of new heavy snow over the old low density surface. I did not find any indications of preserved surface hoar. I was able to isolate 1 ECT - ECTP 1, Q2 @ base of new snow 15 degree slope. All other columns failed on isolation. By the end of the day I was observing a lot of soft cracking while breaking trail and skiing, all in the new snow only. Drifts were getting thick and sensitive on the ridge below willow knob, not set up enough for shooting cracks yet.

Red Flags
Red Flags
Heavy Snowfall
Wind Loading
Cracking
Poor Snowpack Structure
Red Flags Comments
Heavy snow during the day could overload the weak underlaying snow on most aspects. I would expect avalanches in some areas typically considered safe. 1 large crack in west monitor, 75' wide and 8" or so deep, just below the cornice in response to a small cornice drop. The slab slid about 1', I am hesitant to call this an avalanche, more of a wide crack although it did slide, hard call.... I was able to make out old tracks in this area. This area looked to have filled back in on my 2nd trip to the ridge, although visibility was poor enough to make it hard to even see were the edge was, let alone get a good look over it. The new snow is sitting on some very weak surfaces, I think this will release before any of the deeper weak layers (e.g. facets)
Avalanche Problem #1
Problem
New Snow
Trend
Increasing Danger
Problem #1 Comments

New snow over a variety of weak surfaces.

Could increase to high if not already there, i would expect a natural cycle tonight.

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

A lot of loading today!

I would add deep slabs as a 3rd problem if the forecasted amounts pan out.

I would add wet slides at the mid elevations as problem 4.

Comments

About as windy as it gets today!

Trail breaking was becoming harder towards the end of the day.

Fat skis were very helpful in the inverted and drifted snow.

Glad I wore my goretex pants today.

High danger based on getting more snow tonight.

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