Avalanche Occurrence

Photo of a large, intentionally-triggered avalanche above Titus Lake. The avalanche initiated as a hard wind slab (formed during last week's wind) and then stepped down into the December facet layer (visible in the center of the photo). The slide broke approx. 200' wide and ran 800' vertically. 9700', NE. Chris Marshall photo.

Observer:

SAC Forecaster

Verified by SAC?

Yes

Occurrence Date:

Feb 13, 2021 (Exact)

Location:

Titus Ridge (above Titus Lake)

Comments:

Avalanche was intentionally triggered by a skier stomping around on the ridge above. The slide initiated in the hard slabs that formed during the extended wind event in early February. These stiff slabs cracked and pulled back onto very flat (single digit) terrain along the ridge. It stepped down to the early December facets about 15-30' downslope, where the slope angle averaged in the mid to upper 30s.

# of Avys:

Aspect:

NE (E,NE)

Start Zone Elev:

9700ft

Size:

Type:

HS-Hard Slab

Trigger:

AS-Skier
c-Intentional

Bed Surface:

O-Old Snow

Width:

200ft

Vertical Fall:

800ft

Weak Layer:

Dec 11, 2020 (FCsf)

Comments:

Slide initiated in P hard wind slabs along ridgeline and stepped down to 12/11 weak layer about 5-10 meters downslope. 12/11 presented as significantly degraded F+ hard crust above F DH. DH xtals were 4-6mm striated cups, occasionally chained, and bone-dry. Showing no signs of healing in this location. I dug at step-down crown, where 12/11 was 30-50cm off the ground, capped by 60-80 cm thick 4F- to 4F+ slab. I (Ben) did not feel comfortable visiting most of the crown, so many of the characteristics are estimated.