Zone: Southeast Mountains
Location: Cement Creek
Date of Observation: 12/13/2020
Name: Cosmo Langsfeld
Subject: Cement Creek Snow
Aspect:
Elevation: 9250
Avalanches:
Weather: Snow let up around midmorning Saturday, and though it never really quit snowing all day, only another 1.5″ accumulated, bringing storm totals from Thursday night through Sunday morning to ~4.5″. Thermometer said -12 at 6:30am.
Zone: Southeast Mountains
Location: Gunsight Road
Date of Observation: 12/12/2020
Name: Ian Havlick
Subject: Touchy Conditions Mount Emmons
Aspect: North, North East, East, South East
Elevation: 9000-11,200
Avalanches:
Numerous remotely triggered D1 avalanches failing off road cuts within old snow on steep rollovers and raod cuts. Junky facets 30cm deep, new snow 30cm deep in terrain travelled. Slabs were fist+ hard above fist- 2-3mm facets. Fracture line profile on one remote trigger, 10,800ft, NE facing revealed ECTPV (1 tap) and CT3 failing 35cm deep within upper 3cm of old facet surface.
Weather: S-1 to S2 most of the day, some partial midday clearing but no vis into the alpine. calm conditions. Temps 5-17ºF
Snowpack: Simple structure, new snow on top of really weak old snow. same same as other parts of zone. appeared the yesterdays snowfall was slightly denser than todays and slightly denser than the old snow it fell on, creating just barely enough cohesion and hardness difference to allow propagation. Seemed the slab had increased reactivity in the afternoon with increased temperatures and a little more time to consolidate than earlier in the morning. Didnt seem like as much an increase of load (though some was occuring) as evolution of the slab character.
Photos:
Zone: Northwest Mountains
Location: Ponytail glades
Date of Observation: 12/12/2020
Name: JAFAR TABAIAN
Subject: Ponytail glades
Aspect: East, South East, South
Elevation: 11200
Avalanches:
None.
Weather: Snowing. :)
Snowpack: Extreme cracking on S slopes, ran 15-20 feet. Nothing moved on us but slope angle was max 28 degrees. S slopes had a very crusty ice layer near ground. E slopes had un-consolidated loose snow to ground level and skied better. Pretty thin, hiked out the last pitch down to the mine road.
Photos:
Zone: Northwest Mountains
Location: Pittsburg
Date of Observation: 12/12/2020
Name: Joey Carpenter
Subject: Pittsburg
Aspect: North East
Elevation: 9250-10.5k
Avalanches:
Remote trigger (skinning), unintentional, R1D1, 10k, NE, 37 degrees, 45cm storm slab, 40′ wide, 50 vert, ran on November facets (35cm to ground, 1.5-2mm). Cracking extended onto 34-35 degree slopes 30′ to either side of the crown. M/f crust here has deteriorated almost entirely.
Remote trigger (skinning), intentional, R1D.5, 9700k, NE, 36 degrees, 45cm storm slab. 25 ft wide, 30 vert, Nov facets. The 60-80ft skiers left of this slide ran naturally sometime yesterday afternoon.
Skier trigger, R1.5D1.5, 10k, 35 degrees, 45cm storm slab (estimate), ran 60-70 vert, intentional, This slide had the most energy of anything we saw today w/ a ski cut at a convex roll.
At least 2-3 naturals BTL that ran yesterday of similar characteristics to slides described above. Small in overall size entraining only snow from the last 36 hours.
Weather: Overcast skies all day, temps started in single digits and rose to the high teens. No wind or transport. S-1 snowfall throughout the day with about 2″ accumlation from 8a-230p.
Snowpack: Snowpack was very sensitive today. Cracking at every step breaking trail through ~45cm of low density storm snow sitting on top of 35cm of 1.5-2mm facets to the ground. You could still dig to the MF crust from before the Turkey week storm but it was mostly rotted out and becoming part of the facet mess. Shooting cracks, slumping and small avalanches were easily triggered on any slope tipping past 32-33 degrees.
Photos:
Zone: Southeast Mountains
Date of Observation: 12/12/2020
Name: Colorado Backcountry AVY L1
Aspect: North East
Elevation: 10,000
Avalanches:Â 1 Tree Bomb triggered D1
Weather: Overcast, calm, cold. Mostly light snowfall with about 2″ new snow on the cars when we returned to the trailhead.
Snowpack: About a 35cm soft slab, sitting on exceptionally weak facets. When we tried to isolate columns, with hands or ski poles, the columns failed before they were fully isolated. We never felt any collapses, but traveling in areas with slope angles between about 15 to 30 degrees, often produced shooting cracks and blocks of new snow shifting on the facets below.
Zone: Southeast Mountains
Location: Snodgrass
Date of Observation: 12/12/2020
Name: Eric Murrow
Subject: Reactive Slabs on Snodgrass
Aspect: North, North East, East
Elevation: 9,500 – 11,100
Avalanches:
Triggered two avalanches from ridgetop D1’s but enough volume to take you for a ride and pound you into trees and rocks, one on east, one on northeast (see photos).
Observed a natural on a north-facing feature that ran early in the day, as bed surface had just a dusting of new snow, D1.
Weather: Overcast skies, very light winds (trees holding lots of snow), consistent light snow, S-1, between 10am and 230pm accumulated a bit more than an inch.
Snowpack: Storm totals since Friday morning were up to 35cm (13″) at 11,000′, 130pm. Measures SWE was .9″. Snowpack was often ‘trenchy’ with little support on east and north aspects. It was easy to trigger D1 avalanches on slopes greater than 35 degrees that faced north through east. Not enough volume to bury you, but enough to hurt ya from hitting objects. Fractures propagate up to 75 feet. No collapsing or remote triggering experienced. Needed to walk right to the edge of the slope for slabs to break. The weak basal snowpack was quickly entrained as slab ran.
Photos:
Zone: Northwest Mountains
Location: Pittsburg
Date of Observation: 12/12/2020
Name: Sam L
Subject: Cracking, collapsing, avalanching
Aspect: North, North East
Elevation:
Avalanches:
Widespread cracking and collapsing including remote and skier triggered low energy D1s.
Weather: Steady snowfall all day, snowed up to an inch on sleds, seemed more like two at the trail head.
Snowpack: Slides entrained all of storm snow from the past two days and ran on basal facets and seemingly a deteriorated sun crust on more sunny aspects.
Photos:
Zone: Northwest Mountains
Location: Red Lady Glades
Date of Observation: 12/12/2020
Subject: Red Lady glades pow tour
Aspect: North East, East
Elevation: 11200
Avalanches:
Small R1/D1 avalanche path noticed at 11200 feet. Most likely intentional from the skier before me skiing on the SE facing skin track.
Weather: Snowing, low visibility,1 5 degrees
Snowpack: 70 cm depth
Photos:
Zone: Northwest Mountains
Date of Observation: 12/12/2020
Name: Alex Tiberio
Subject: Gothic Obs
Aspect: North East, East
Elevation: 10,000
Avalanches:
Weather:
Snowpack: Lots of shooting cracks on our low angle tour, propagating large distances. Entire meadows would all collapse at once.
Photos:
