Location: Paradise Divide Area
Date of Observation: 12/05/2019
Name: Evan Ross & Zach Kinler

Subject: Site Visit Of Human Triggered Avalanche Near Pittsburgh
Aspect: North East
Elevation: 10,200

Avalanches: Quick site visit of a recent snowboarder triggered avalanche.

This was a soft slab avalanche failing near the ground on a persistent weak layer of faceted grains. The avalanche size was large enough to bury a person. The avalanche ran for about 400ft of elevation loss and was about 100ft wide before gaining additional width as the avalanche moved down hill. The crown hight is estimated to be around 2.5ft, or 80cm. A snow profile at 9,800ft is in the picture below. In a brief summary there was 10 to 12″ of very soft new snow, over a 4F slab, sitting above the weak faceted grains below. Slope angles for this area are shown on CalTopo with slope shading in the 35-45 degree band, and further estimated to be at the lower half of that scale.

Location: Crested Butte Area
Date of Observation: 12/05/2019
Name: Alex Tiberio

Subject: Gothic Obs
Aspect: North East
Elevation: 10000

Weather: Snowy and windy in AM clearing up in PM
Snowpack: 10” of new snow from storm. Fairly large collapses in open meadows on slopes less than 30 degrees

Photos:

Location: Paradise Divide Area
Date of Observation: 12/05/2019
Name: Derel Zazzi

Subject: Rider Trigger Avalanche
Aspect: North East
Elevation: 10,000

Avalanches: north east aspect rider trigger avalanche. first rider triggers avalanche and gets flushed for full pitch. ends up in debris pile. 2nd rider digs first rider out, partially buried.

Weather: Snowing Heavily thru the duration of the ski day.

Location: Crested Butte Area
Date of Observation: 12/05/2019
Name: billy bar

Subject: Gothic 7am Weather Update

Weather: Snow started near midnight and was steady most of the night, pausing near sunrise. There was 6″ new and 0.42″ and snow pack is at winter’s deepest of 15″. Currently it is overcast but just stopped snowing. No wind through the night. Yesterday’s high was 42F and it dipped to 14F after dark but is currently at 25F. A nice snow.

Location: Paradise Divide Area
Date of Observation: 12/04/2019
Name: Evan Ross

Subject: Shooting Cracks, Poverty Gulch
Aspect: North, North East
Elevation: 9,500-10,500

Weather: Mostly cloudy sky in the morning cleared out to few clouds through the day. The cloud bank still didn’t make it overhead at sunset. Calm wind down in the valleys and nice warm temps.
Snowpack: The slabs that formed in late November are holding up well. Ski Pen was around 10-15cm, with Boot Pen punching through to the old October snow on the ground. That old snow is just as weak as it ever was, 2-3mm faceted and striated grains. So, classic Persistent Slab Avalanche Problem. HS was in the 40-60cm range, but the slabs held the skis up just fine and made the skiing great if you could dodge all the shrubs and ground clutter.

Plenty of collapses with shooting cracks were felt. Didn’t take slope angles over 33 degrees and made sure to give overhead slopes plenty of room with the threat of remote triggering them. The shooting cracks were failing at the interface of the October snow. There were a couple other weak interfaces in this shallow snowpack, with layers of SH and small NSF. Whole bunch of junk, but at least the slabs were keeping you off the ground.

Location: Paradise Divide Area
Date of Observation: 12/04/2019
Name: Zach Kinler

Subject: Elkton Study Plot
Aspect: North East, East, South East, South, South West, West
Elevation: 10,400

Avalanches: No new avalanches observed.

Weather: FEW, Light West winds, Tair @12:40 was +1.0C. Strong solar, very comfortable day!

Snowpack: HS only increased by 3 cm since last Wednesday despite ~25 cm accumulation during the week. This settlement has created a 1F- hard slab sitting on top of the 11/25 Interface which is 2 mm facets capped with a 1 cm faceting crust. This structure, with the stiffer slab, was able to produce easy CT results (CT5 SC Q1) and propagating ECT results (ECTP10).

Moderate CT results (CT 20 RP Q2) and non-propagating ECT results (ECTN12) were observed at the 11/29 interface which consists of 1.5 mm near surface facets.

Location: Kebler Pass Area
Date of Observation: 12/01/2019

Subject: Good Coverage at Rainbow Lake
Aspect: South
Elevation: 10,698

Snowpack: above 10,200 the snow starts to stack up… in the sheltered trees BTL the snow and skiing is pretty good. ATL more wind effected as you’d expect.

Location: Kebler Pass Area
Date of Observation: 12/03/2019
Name: Sam Roberts

Subject: Red Lady Glades
Aspect: East, South East, South
Elevation: 9,000′-11284′

Avalanches: None

Weather: The day started as mostly overcast with a few flakes flying and a slight wind coming in from the west. As we skinned the clouds began to break and the wind remained with the occasional gust up to about 10mph. The decrease of cloud coverage saw an increase in sunlight and the temperature rose quickly from around -5 degrees C to about +1 degrees C by noon.

Snowpack: VERY THIN. Overall the glades are a 100% no-go and I would not recommend them to any friends or family just yet. We went up anyway. The skin track is the usual track but with many more logs and bushes in the way. We skinned until we reached the rim of red lady bowl the went west into the glades for a pit. The pit was just as we expected from the skin up, shallow. Snow totals ranged from 25-45 cm total in a E-SE-S facing gully at 11284′. There were 2 distinct layer, the first being the last storm snow that consisted of rounded grains of fist hardness (with the basal 2-3cm developing into facets) ranging from 20-40cm below a 2-4cm thick sun crust. Above the sun crust was 3-5cm of fresh snow that had been blown in by the wind. No test were conducted, the only reactivity I saw was the 2cm sun crust cracking and sliding on top of the storm snow. This quickly degrading new snow under that sun crust could cause problems whenever this area gets more snow.