Observation: Red Pine Gulch

Observation Date

12/22/2014

Observer Name

Patrick Fink

Region

Salt Lake » Little Cottonwood Canyon » Red Pine

Location Name or Route

Red Pine

Weather

Sky

Overcast

Precipitation

Moderate Snowfall

Wind Direction

Southwest

Wind Speed

Strong

Weather Comments

Snowing at the white pine lot around 11:00 am when we started our tour. The precip waned and stopped entirely around 12:00, before returning with a vengance at 2:30. During this time there was significant accumulation of large-diameter grauppel (2-3mm) and an increase in winds from earlier in the day. The winds were generally strong, though gusting, and varied on a local scale from S-SW-W.

Snow Characteristics

New Snow Depth

18"

New Snow Density

High

Snow Surface Conditions

Dense Loose

Rain-Rime Crust

Damp

Snow Characteristics Comments

Biggest observation of the day was a rain crust which extended to the high point of our tour at 9350'. In Red Pine, valley floor was coated by a thin creme-brulee coating of ice which was buried in dense-wind transported snow in locally wind-favored areas. Overlying the crust was dense 4f+ wind slab with a dusting of grauppel. In lower elevations of white pine, oddly, the rain crust was not a big player. It was present in hand pits, but was poorly defined and less crusty-- more like very dense, saturated, semi-frozen rounds.

Red Flags

Recent Avalanches

Heavy Snowfall

Wind Loading

Rapid Warming

Poor Snowpack Structure

Red Flags Comments

Poor snowpack structure remains from prior to the storm and includes an inverted structure in yesterday's snow. The precip that we saw today was of lower density, however wind transport was forming this into dense slabs. Wind transport obscured our skin tracks within 40 minutes. Recent avalanches were observed across the valley in all of the south facing avalanche paths. There was decent visibility at times and we could see no recent avalanches in Red Pine. Wind loading was, I think, a more significant factor than the new precipitation, as it was happening quickly on almost all aspects W-N-E. Only very exposed areas, like ridge lines, were being scoured. The new snow was hardly resting on the ground before being turned into a slab. To my surprise, we elicited no cracking, collapsing, or failures on small test slopes, despite trying our best.

Avalanche Problem #1

Problem

Persistent Weak Layer

Trend

Increasing Danger

Problem #1 Comments

Ranking this concern 1 because it is ongoing and significant, and could become the load needed to trigger deeper instabilities before they've healed. They are, by themselves, stiff and unpredictable hazard on the W-N-E aspects that we observed.

Avalanche Problem #2

Problem

Persistent Weak Layer

Trend

Decreasing Danger

Problem #2 Comments

This is the lurking issue-- that we saw no local evidence of instability like cracking or collapsing could be considered encouraging, but knowing that the snowpack has poor structure, this lack of results is just creepy. It seems like though they could be hard to trigger, there are slides waiting to break down to near the ground with the right provocation, and this hazard is hard to predict. Hopefully, this will become less of an issue as some cooler weather turns the wet precipitation into a solid bridge over basal instabilities. I'm marking it improving, but it could take a minute.

Today's Observed Danger Rating

High

Tomorrows Estimated Danger Rating

Considerable

Learn More

Take a Class

How To

Help the Community

Upcoming Events

Observations & Avalanches