Observation: Days Fork 12/29/2011

Observer Name:

Bruce Tremper

Observation Date:

12/29/2011

Region:

Salt Lake
Big Cottonwood Canyon
Days Fork

Weather

Sky:

Overcast

Wind Speed:

Moderate

Weather Comments:

Warm, cloudy and windy but with no precipitation

Snow Characteristics

New Snow Depth:

New Snow Density:

Medium

Snow Surface Conditions:

Powder

Snow Characteristic Comments:

The snow was quite damp below about 8,500'. Dry above 8,500' with 3 inches of dense graupel on top. In places above about 9,000' you can find a thin rain crust just beneath the graupel. In most areas it is quite thin and hard to detect, but in other places it is thicker. I'm not sure why there is such variability as rain is usually fairly evenly distributed. It could be that in some places there is a sun and wind crust as well, which makes tracking this thin crust hard. It will be interesting to see how this affects metamorphism during the coming colder weather and high pressure.

Red Flags

Wind Loading

Red Flag Comments:

No big red flags today but there was some localized wind loading along the upper elevation ridges. Winds are forecast to pick up and blow harder on Friday and Saturday from the west. So we will have to carefully watch for any recent deposit of wind drifted snow.

Primary Concern

Primary Concern:

Wind Slabs

Probability:

Moderate

Aspect:

North

Northeast

East

Southeast

South

Southwest

West

Northwest

Elevation:

High

Trend:

More Dangerous

Primary Concern Comments:

The main concern is wind loading. The preexisting snow is extremely weak, deep, faceted snow in all areas. I could see some wind loading today with the moderate winds on many of the upper elevation slopes and with the forecast of stronger winds on Friday and Saturday, we should have some dangerous wind slabs in upper elevation, wind exposed areas.

So as always, avoid any steep slope with recent wind drifts because it will almost certainly be dangerous with the stiff, heavy wind slab on top of the extremely weak, faceted snow. It won't take much.

snow_profile_location:

Comments - Photos - Videos (group 1)

I have a 1 minute video of fieldwork in Days Fork in Big Cottonwood Canyon. You can see the extremely weak, faceted snow and how it behaves at lower elevations where it is quite damp and at upper elevations where it is dry.

Video 1:

Observed Danger Rating:

Moderate

Forecast Danger Rating:

Considerable