Details

• Date: 2018/02/16

• Observer: blase reardon
• Organization: Forecaster, CAIC

Location

• BC Zone: Aspen
• Area Description: Various locations in the Roaring Fork Valley, including Aspen Mountain.

Weather

• Ridgeline Wind Speed: Unknown
• Temperature: 24 F
• Sky Cover: Scattered
• Weather Description: Clear skies gave way to high, thin clouds. Never fully overcast. Winds L-M but picked up as afternoon progressed. Widespread blowing and drifting snow at ridgelines. HSTW 0.6" at Ashcroft.

Avalanches

• Avalanche Description: Natural cycle of large avalanches at all elevations, mostly on NW-NE-E facing slopes prone to loading or cross-loading. Activity concentrated around Snowmass and Capitol Creeks; less in Castle Creek. Most slides had little snow on the bed surfaces, indicating they ran late in the storm or after the snowfall stopped (midnight?). Most slides broke near the ground, though some flanks pulled out mid-pack. Most notable slides listed below (that aren't included in other reports).

	Date	Location/Path	#	Elev	Asp	Type	Trig	SizeR	SizeD
	2018/02/16  †	Richmond Hill	1	<TL	NE	SS	N	R3	D3
Date: 2018/02/16 (Estimated) Observer: blase reardon Organization: Forecaster, CAIC Area Description: McFarlane's Bowl. Part of A, all of B, and part of C. Landmark: Richmond Hill Elevation: 10750 ft Sliding Surface: O - Within Old Snow Average Crown: 300 in Maximum Width: 550 ft Maximum Vertical: 1000 ft Comments: With50-75% Happy Face slide 2-14, 50-75% of the boal ha slid. The debris ran out of sight. A deep secondary fracture occurred in the northerly glades below the exit road.
	2018/02/16  †	Richmond Hill	1	<TL	N	SS	AS / r	R2	D2
Date: 2018/02/16 (Estimated) Observer: blase reardon Organization: Forecaster, CAIC Area Description: Black Diamond Bowl, Richmond Ridge. Next bowl south of McFarlane's. Landmark: Richmond Hill Elevation: 10950 ft Sliding Surface: O - Within Old Snow Average Crown: 2 in Maximum Crown: 3 in Maximum Width: 100 ft Maximum Vertical: 600 ft Comments: 4th skier was near bottom when slope collapsed on remaining skiers in party. 2 skiers barely on wrong side of crown. One slid a few feet down; both remained standing. ~1/3 of this slope had slid earlier in the winter.
	2018/02/16  †	Maroon Creek	1	TL	NW	U	N	R3	D2.5
Date: 2018/02/16 (Estimated) Observer: blase reardon Organization: Forecaster, CAIC Area Description: Desolation Row, adjacent to Aspen Highlands ski area. Landmark: Maroon Creek Elevation: 11600 ft Sliding Surface: O - Within Old Snow Average Crown: 36 in Maximum Crown: 48 in Comments: Don't know if it ran full path to creek. Start zone prone to cross-loading.
	2018/02/16  †	Richmond Hill	3	<TL	NW	SS	AS / c	R1	D1.5
Date: 2018/02/16 (Estimated) Observer: blase reardon Organization: Forecaster, CAIC Area Description: Bingo Glades, Aspen Mountain Landmark: Richmond Hill Elevation: 9150 ft Sliding Surface: O - Within Old Snow Average Crown: 20 in Maximum Crown: 30 in Average Width: 15 ft Comments: 4F Depth Hoar, 1F consolidated snow (~15cm thick), F hard new snow (15+").
	2018/02/16  †	Maroon Bells-Snowmass Wilderness	2	>TL	NE	U	N	R2	D2.5
Date: 2018/02/16 (Estimated) Observer: blase reardon Organization: Forecaster, CAIC Area Description: Elk Ridge, East Sopris Creek Landmark: Maroon Bells-Snowmass Wilderness Comments: Larger of two below cliffs and well below ridge.
	2018/02/16  †	Richmond Hill	3	<TL	N	SS	AS / c	R1	D1.5
Date: 2018/02/16 (Estimated) Observer: blase reardon Organization: Forecaster, CAIC Area Description: Silver Queen Ridge Landmark: Richmond Hill Elevation: 8800 ft Sliding Surface: O - Within Old Snow Comments: Patroller caught and carried short distance.
	2018/02/16  †	Maroon Bells-Snowmass Wilderness	1	>TL	E	U	N	R2	D2.5
Date: 2018/02/16 (Estimated) Observer: blase reardon Organization: Forecaster, CAIC Area Description: Elk Ridge, East Sopris Creek Landmark: Maroon Bells-Snowmass Wilderness Elevation: 12000 ft Comments: Below but near ridge. Wider crown than nearby slides, but shallower.

Media

Images

Figure 1: Orange line marks the crown of a remotely-triggered avalanche in Black Diamond Bowl, Richmond Ridge. Arrow marks approximate trigger point. Slope to looker's right cracked but did not slide. Easterly, below treeline. 2-16-18

Figure 2: Looking at the crown of a remotely-triggered avalanche, BlackDiamond Bowl, Richmond Ridge. The lower angled slope cracked but did not slide. 2-16-18.

Figure 3: McFarlane's Bowl, Richmond Ridge. Orange line marks part of crown from 2-16-18 natural avalanche. 2-14 slide triggered remotely from ridge above.

Figure 4: Part of the crown of a natural avalanche in McFarlane's Bowl, Richmond Ridge. 2-16-18.

Figure 5: Part of the debris field from a lage natural avalanche in McFarlane's Bowl, 2-16-18. Orange line marks secondary fracture on flank; blue marks exit road.

Figure 6: By late afternoon, west winds had picked up and were drifting and blowing the storm snow on exposed ridges. 2-16-18.

Figure 7: Part of the crown of a large natural avalanche in Desolation Row, just south of Maroon Bowl, adjacent to Aspen Highlands. 2-16-18

Figure 8: Deep fracture along the flank of a natural avalanche in McFarlane's Bowl, Richmond Ridge. 2-16-18