Avalanche: White Pine 3/16/2011

Observer Name:

Havlick/Hardesty

Observation Date:

03/18/2011

Occurrence Date:

03/16/2011

Occurrence Time:

Unknown

Region:

White Pine
Little Cottonwood Canyon
Salt Lake

Location Name:

White Baldy

Location

40° 32' 3.3828" N, 111° 40' 50.6856" W

Avalanche Characteristics

Elevation:

10700'

Aspect:

Northeast

East

Slope Angle:

Trigger:

Natural

Trigger: additional info:

Cornice Triggered

Avalanche Type:

Hard Slab

Weak Layer:

Surface Hoar

Depth (avg):

Depth Range:

4' to

11'

Width:

300'

Vertical:

500'

General Comments

Drew and I skied up to check out Fred Staff's report of large natural avalanche in upper white pine today...and we were not let down. Likely triggered Wednesday night based of the recent deposit of dust layer, associated with the most recent snowfall. After investigating the huge crown, it was clear the slide initiated from an unknown sized cornice fall (guessing pretty large) tumbling onto a slightly thinner portion of the 'hanging snowfield,' breaking around 4ft deep and propagating in both directions, ~300ft+ total, running on buried surface hoar below the MLK rain crust.

TAKE HOME: very large avalanche, (~R3-D3.5), initiated by a heavy cornice trigger and no compressive support (hanging snowfield resting above rock bands).

Photo below of 7mm decaying January Surface Hoar - that and weak 2-3mm facets - the failure plane there beneath the January MLK rain crust -

Video 1:

General Comments 2

Crown and looming cornice

General Comments 3

Drew at deepest portion of crown. Humbling.

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