Zone: Northwest Mountains Route Description: Rode on northerly aspects of East and West Beckwith to about 11,300′
Observed avalanche activity: Yes Avalanches: Noted 3 shallow soft slabs that ran naturally above treeline sometime in the past few days, D1 in size. Added a couple more previously undocumented old slides from the 12/31 cycle on West Beckwith. I explored the damage from the largest slide on West Beckwith. The crown in the main bowl was about 2,200 ft wide. It’s difficult to tell if it connected or sympathetically released another slide in the adjacent bowl, which would add another 1,500 ft in width. The slide in the main bowl ran about 3,800 feet downhill. It widened the trim line on either side of the track and wiped out about 2+ acres of mature forest at the toe of the debris. I measured the alpha angle at 19 degrees on my phone’s inclinometer, and calculated 18 degrees on Google Earth. Weather: Clear skies this morning increased to overcast this afternoon. Light winds. Snowpack: I found 2-3 mm surface hoar growth from below treeline to my high point at 11,300 ft. There’s been enough recent wind effect in this area to reduce the threat of sluffs near and above treeline and replace it with small wind slab potential. I sniffed around a bit for wind slabs and got one rollover near treeline to produce 10 foot cracking about 10 inches deep on the 1/21 facet layer. No other signs of instability. The snowpack gets shallower the further west in the range you go. Near the western end of West Beckwith, snow depth at 10,000 ft is 1 meter. The slab there is faceting away and becoming unsupportive to boot pen.
Photos:
Surface hoar growth reaching into the alpine
Old deep slab crown on from 12/31 cycle on West Beckwith (Previously documented))
Trim line widened
Mature trees knocked over near the terminus of the debris
Estimated extend of the largest avalanche on West Beckwith. The lookers right lobe may have been a separate event.
Cracking in a wind drifted rollover near treeline
One of several small soft slabs that ran sometime in the past few days.
Estimated avalanche date: 12/31/2021 Number of Avalanches: 2
Location
Location: Beckwith Range Location Specific: Start Zone Elevation: ATL: Above Tree Line Aspect: N
Characteristics
Trigger: Natural Trigger modifier: Type: Hard Slab Failure Plane: Old snow
Size
Relative Size: R2 small Destructive Size: D2.5 Avg. crown height (inches): Avg. width (feet): Avg. vertical run (feet):
Involvements
# of people caught: # of partial burials: # of full burials:
Additional comments: A couple of smaller hard slabs from the big cycle in northerly bowls of West Beckwith. Crowns and debris are mostly covered, so these could have been larger than I estimated.
Relative Size: R1 very small Destructive Size: D1- Relatively harmless to people Avg. crown height (inches): Avg. width (feet): Avg. vertical run (feet):
Involvements
# of people caught: # of partial burials: # of full burials:
Additional comments: West Beckwith. Uncertain of failure date. Could have been with last night’s increased winds or a few days ago with the storm.
Relative Size: R1 very small Destructive Size: D1- Relatively harmless to people Avg. crown height (inches): Avg. width (feet): Avg. vertical run (feet):
Involvements
# of people caught: # of partial burials: # of full burials:
Additional comments: West Beckwith. Uncertain of failure date. Could have been with last night’s increased winds or a few days ago with the storm.