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Observation: Catherine's Pass

Observation Date
11/17/2013
Observer Name
Justin Lozier
Region
Salt Lake » Little Cottonwood Canyon » Catherine's Pass
Location Name or Route
Catherine's Area
Weather
Sky
Broken
Wind Direction
West
Wind Speed
Moderate
Weather Comments
Moderate-Strong winds overnight: 20-30 mph average, gusting to 50+ out of the WSW @ 11,000'. Cold temps overnight: mid-20's @ 8,550', 14 degree low @ 11,000'.
Snow Characteristics
New Snow Depth
12"
New Snow Density
Medium
Snow Surface Conditions
Powder
Dense Loose
Snow Characteristics Comments
Strong overnight winds contributed to widespread wind loading and wind-compacted snow in most areas. Slabby conditions were found in most of the leeward upper elevation terrain. Many areas were so deep and dense from extensive wind loading that the skiing was challenging on the lower angle terrain.
Red Flags
Red Flags
Heavy Snowfall
Wind Loading
Poor Snowpack Structure
Red Flags Comments
Almost an inch of water fell on the existing weak snowpack overnight, plus moderate to strong winds transporting the new snow, creating deep wind drifts and wind slab conditions. The snowpack structure is poor: a foot of new snow (deeper in wind loaded areas); wind slabs on lee upper elevation slopes; thin, wind scoured areas on windward upper elevation slopes; weak facet/depth hoar layer about a foot thick at the bottom of it all on most upper elevation north-facing slopes.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Decreasing Danger
Problem #1 Comments
Fairly cohesive wind slab on most lee upper elevation slopes. No cracking noted, not a particularly stiff slab. Slab cohesion will likely break down with diurnal recrystallization.
Avalanche Problem #2
Problem
New Snow
Trend
Increasing Danger
Problem #2 Comments
The base of the snowpack is completely rotten: a foot of 2-3 mm faceted crystals and depth hoar. Upcoming cold, clear nights will continue the faceting process throughout the snowpack with steep temperature gradients.
Snow Profile
Aspect
North
Elevation
10,200'
Slope Angle
30°
Comments
We were the second group on top of Catherine's Area early in the morning, before the malay of latecomers made a mess of the place. Our first run was good, a bit more wind-pressed than we had hoped, but just about as cross-loaded as we had expected. By the time we finished our snow profile on our way up for our second lap, the horde was upon us, so we bailed back to the parking lot. We got what we wanted: powder turns and snow data.
Photo of our pit wall, illustrating snowpack stratigraphy
Photo of 10x magnified faceted crystals and depth hoar grains, size 2-3mm
Coordinates