Observation: Alta Periphery

Observation Date
1/25/2013
Observer Name
Evelyn
Region
Salt Lake
Location Name or Route
Alta periphery
Weather
Sky
Overcast
Precipitation
Light Snowfall
Wind Speed
Calm
Weather Comments
Sky obscured above about 10,000', with the peaks in the clouds. Occassional light snow at these elevations. minor riming, not on snow surface, but on other objects.
Snow Characteristics
New Snow Depth
4"
New Snow Density
High
Snow Surface Conditions
Powder
Dense Loose
Damp
Snow Characteristics Comments
The new snow varied widely by elevation. Dense, loose powder above about 9,500 feet, damp snow below.
Red Flags
Red Flags
Recent Avalanches
Cracking
Rapid Warming
Poor Snowpack Structure
Red Flags Comments
Low elevations: just about every north facing gully from the canyon mouth to Red Pine had slid at least once. Wet loose slides. Upper elevations: cracking and poor structure on northerly facing slopes.
Avalanche Problem #1
Problem
Wet Snow
Problem #1 Comments

Checked out the snow at a couple low elevation spots from the mouth to about 7600' - damp punchy snow snow, where you can sink all the way to the ground. Saturday, the widespread natural cycle may be about over, with just isolated naturals possible. Human triggered slides will still be possible on steep slopes. In the longer term, this heating is great - once there is more settlement and cooling, the lower elevations will have a strong snowpack.

Avalanche Problem #2
Problem
New Snow
Problem #2 Comments

The below snow pit and test result is an example of where there is now a slab sitting on the weak, upper most January near surface facet layer. The dense new snow, while shallow and not having much weight, does have slab characteristics, and the weak layer/slab combo was able to propagate a fracture.

The variability of the snow pack has increased greatly at the upper elevations during the January dry spells. There are now a surprising number of shallow areas that seem to be pockety, but are faceted to the ground.

Photos of the needles that were falling. They generally form in warm, super saturated conditions, which fits yesterday's upper elevation conditions. Second photo of riming occurring on a tree branch, though I was not finding any riming on the snow surface.