Observation: UFO Bowls

Observation Date
01/11/2016
Observer Name
Hardesty

Region:

Location Name or Route
UFO Bowls
Weather
Sky
Few
Wind Direction
Northwest
Wind Speed
Moderate
Weather Comments
Plumes noted along the high Timp massif; however many areas (including ours) are protected from the northwesterlies. Cold in the draws and canyons along the east side of Timp; temps there in the single digits. Surface hoar noted perhaps more prominently at higher elevations and this (speculatively) attributed to Sunday's alto-stratus. Large stellars noted on the snow surface; SH growing on some of the arms - pics below.
Snow Characteristics
New Snow Depth
12"
New Snow Density
Medium
Snow Surface Conditions
Powder
Damp
Snow Characteristics Comments

A+ skiing and riding conditions.  Southerly aspects affected by the sun briefly yesterday; though full brunt peeled out some longer running size 1&2 WL on Timp today on south/southwest.  

Last week's 18" settled to 12".  

Red Flags
Red Flags
Recent Avalanches
Rapid Warming
Poor Snowpack Structure
Red Flags Comments
Skier triggered sluffs noted on steeper terrain, running 350' - pic below.... Natural dry sluff-triggered soft slab pocket noted in mid-Primrose Cirque estimated 2' deep 30' wide SE facing 9000' - pic below.... Natural wet loose noted up to Size 2 on steep sustained south/southwest flanks of Timp - pic below....
Avalanche Problem #1
Type
Persistent Slab
Trend
Increasing Danger
Problem #1 Comments

Problems with repeaters from the pre-Christmas cycle.  10-15cm of very weak snow not cleaned out by cycle.   40cm or so of new sits above this old layer.  Holy Toledo, El Rollo, likely Upper Days serve as indicators of repeater activity.  At 9600' northeast near the UFO Bowl/Primrose ridgeline, the other avalanche professional and I didn't love the set-up and turned around.  Professional over personal risk assessment.  

We also dug at 8500' northeast facing with HS of 120cm; seemed to have gained quite a bit of stability over the weeks...Profiles below.

Increasing danger below is attributed to winds likely seen elsewhere that may have made this repeater structure more unstable. 

Snow analysis done in this repeater in the South UFO Bowl, below


Avalanche Problem #2
Type
Loose Wet Snow
Problem #2 Comments

Low density snow, steep sustained terrain, first heating of direct sun.  Never mind temps remained in the teens...

Snow Profile
Aspect
Northeast
Elevation
8500
Slope Angle
25
Comments

Photos below:

4-5mm Stellars that were originally mistaken as surface hoar

SH growth on said stellars

Primrose Cirque pocket

Ski tracks adjacent to naturals from end of 18" storm Jan 5-8th

‚ÄčNorthwest winds

Skier triggered sluffs on Bob's Knob above Aspen Grove

Surface Hoar

Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate
Snow Profile Coordinates