Details

• Date: 2020/02/11

• Observer: Ryan Lewthwaite
• Organization: Forecaster, CAIC

Location

• BC Zone: Front Range
• Area Description: Mount Trelease east of Loveland Resort.

Weather

• Ridgeline Wind Speed: 5-10 mph
• Ridgeline Wind Direction: SW
• Wind Loading: Light
• Temperature: 15.6 F
• Sky Cover: Clear
• Depth of New Snow: 1 cm
• Depth of Total Snow: 193 cm
• Weather Description: A cold clear morning with -5F degrees. Light winds from the southwest were transporting snow into banners at ridgelines.

Snowpack

• Snowpack Description: Todays snowpits were focused on southeast aspects near and above treeline. A very similar snowpack structure exists on this aspect in these elevation zones with subtle differences. Near treeline slopes have a deeper snowpack that has been less effected by superficial wind. Above treeline there exists a surface windskin that is thin and unsupportable. Both elevation zones have new snow over older 1F hardness slabs with facet/crust combos underneath. It is the facet/crust sandwiches that are most likely to be effected by human triggering causing avalanches. Near treeline test results: CT25@99BRK; CT22@125BRK, ECTX; PST36/100Arr@110. Above treeline test results: CTN; CT19@34BRK; ECTX

Avalanches

• Avalanche Description: The post-storm avalanche cycle showed itself today in the Front Range Mountains. Avalanches were caused by explosive charges dropped from helicopters and thrown by ski patrollers, naturally occurring, and remotely triggered by humans.

	Date	Location/Path	#	Elev	Asp	Type	Trig	SizeR	SizeD
	2020/02/11  †	Dry Gulch	1	<TL	SE	SS	AR / r	R3	D2.5
Date: 2020/02/11 (Estimated) Observer: Ryan Lewthwaite Organization: Forecaster, CAIC Area Description: Mount Trelease southeast face below treeline on an exposed slope that steepens amidst a rock band. Remotely triggered from 30 degrees slope 300 feet east of avalanches flank. Landmark: Dry Gulch Average Slope Angle: 38 ° Maximum Slope Angle: 40 ° Elevation: 11500 ft Sliding Surface: G - At Ground/Ice/Firm Weak Layer: Layer Weak Layer Grain Type: Depth Hoar Average Crown: 48 in Maximum Crown: 96 in Average Width: 900 ft Maximum Width: 1000 ft Average Vertical: 200 ft Maximum Vertical: 250 ft Comments: Was moving through a treed slope when I noticed deep cracks in the soft snow around me. Looked around a rock feature and a slab avalanche had propagated horizontally from the cracks underfoot.
	2020/02/11  †	Dry Gulch	1	>TL	E	C	N	R1	D1.5
Date: 2020/02/11 (Estimated) Observer: Ryan Lewthwaite Organization: Forecaster, CAIC Area Description: Mount Trelease east face above treeline on the exposed ridgeline had a cornice fall that released a small slab avalanche. Landmark: Dry Gulch Average Slope Angle: 39 ° Maximum Slope Angle: 41 ° Elevation: 12300 ft Sliding Surface: S - Within Storm Snow Weak Layer: Layer Weak Layer Grain Type: Decomposing or Fragmented Average Crown: 12 in Maximum Crown: 16 in Average Width: 75 ft Maximum Width: 80 ft Average Vertical: 175 ft Maximum Vertical: 200 ft
	2020/02/11  †	Loveland Pass-Northside	1	TL	NW	C	N	R2	D2
Date: 2020/02/11 (Estimated) Observer: Ryan Lewthwaite Organization: Forecaster, CAIC Area Description: Mount Sniktau. Below the tightest switchback on the Eastside of Loveland Pass, on a northwest aspect a Cornice fall triggered a slab avalanche. The avalanche ran into a drainage Landmark: Loveland Pass-Northside Average Slope Angle: 35 ° Maximum Slope Angle: 38 ° Elevation: 11600 ft Sliding Surface: S - Within Storm Snow Weak Layer: Layer Weak Layer Grain Type: Decomposing or Fragmented Average Crown: 14 in Maximum Crown: 20 in Average Width: 100 ft Maximum Width: 150 ft Average Vertical: 200 ft Maximum Vertical: 250 ft

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