Details

• Date: 2016/12/26

• Observer: Mauri Dimeo
• Organization: Public

Location

• BC Zone: Front Range
• Area Description: Geneva Basin, guanella pass

Weather

• Weather Description: Geneva Basin, SE aspect, 11,000ft. Clear and very windy, some gusts strong enough to knock a person over.

Snowpack

• Snowpack Description: Geneva Basin, SE aspect, 11,000ft. Wind slab over depth hoar. The entire SE face of the bowls slid since I was there 48hours ago. A snowpit (Dug on 12/24/16) picture is shown below. The Very Large avalanche initially failed at a weak layer above the ground, but did step to the ground a short distance below the crown.

Avalanches

• Avalanche Description: The slab that slid went big, R5 and at least D3 and down to the ground. It looks like there were smaller slides on wind loaded slopes that triggered the persistent weak layer at convex rolls. Crown for the persistent layer was about a half mile wide and was over a meter thick at the thickest. The slab propagated around terrain features and even slid on lower angle slopes of about 30degrees. There was a smaller slide to the north that had a deep crown but did not propagate beyond the slope.

	Date	Location/Path	#	Elev	Asp	Type	Trig	SizeR	SizeD
	2016/12/24  †	Guanella Pass	1	TL	SE	HS	N	R2	D1.5
Date: 2016/12/24 (Estimated) Observer: Mauri Dimeo Organization: Public Area Description: Geneva Basin area Landmark: Guanella Pass Elevation: 11000 ft Average Crown: 36 in Average Width: 150 ft Average Vertical: 100 ft Comments: Looks to have run on old snow. Dimensions estimated from photograph
	2016/12/24  †	Guanella Pass	1	TL	SE	HS	N / y	R3	D2.5
Date: 2016/12/24 (Estimated) Observer: Mauri Dimeo Organization: Public Area Description: Geneva Basin. This avalanche may have been sympathetically triggered by a nearby natural Wind Slab avalanche. Landmark: Guanella Pass Average Slope Angle: 30 ° Elevation: 11000 ft Sliding Surface: G - At Ground/Ice/Firm Average Crown: 36 in Maximum Width: 2600 ft Comments: This was a very large avalanche.

Media

Images