Observation: UFO Bowls

Observation Date

1/11/2016

Observer Name

Hardesty

Region

Provo » Provo Canyon » North Fork Provo R. » UFO Bowls

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

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

Problem

Persistent Weak Layer

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.