Observations

Date of Observation: 03/29/2021
Name: Eric Murrow

 

Zone: Southeast Mountains
Location: West Brush Creek towards White Mountain
Aspect: North, North East, East, South East, South, South West, West, North West
Elevation: 9,000 – 12,300′

 

Avalanches: Lots of previous Wet Loose from steep sunny areas all small in size. Did not observe any fresh loose avi’s while in terrain between noon and 5pm. One fresh Wind Slab observed at 12k on NE slope.
Weather: Mostly clear skies with warm temperatures. Strong SW winds at upper elevations with gusty conditions below treeline. Snow transport was generally inefficient due to high speeds blasting snow into the atmosphere; isolated features picked up loading.
Snowpack: Traveled through a shallower part of the forecast area moving through shady slopes near and above treeline. Snowpack on north and northeast slopes at upper elevations was generally in the 130 to 180cm range. A test profile in a drifted location(northeast) with 200cm had a slab around 55cm thick (up to 1 finger hard) resting on the mid-March weak layer and did not produce results in standard test but hard hammering was able to get a propagating result. At a shallower location with HS around 135cm, I tested the basal weak layer which produced a moderate propagating result in the Depth Hoar (4-finger minus hardness) near the ground. Even though triggering a large avalanche in old, weak snow at the ground is on the low end of the probability scale, the variability of snow depth in this part of the forecast area made me a bit selective with my terrain choice by avoiding rocky, variable depth slopes.

Briefly traveled across a few sunny features between 10,000 – 11,200′ and found a few inches of wet snow at the surface, but no significant Wet Loose problem. I suspect some steep, wind-protected sunny slopes were in condition for human-triggered small Wet Loose slides. Low elevation northerlies became moist by the afternoon, but neighboring steep slopes did not produce any natural activity.

 

Photos:

Date of Observation: 03/29/2021
Name: Jack Caprio

Zone: Southeast Mountains
Location: Mount Emmons
Aspect: North, North East, East
Elevation: 9k-12.5k

Avalanches: Small wet loose activity on east-facing slopes of all elevations. SW and W facing slopes had more wet loose activity below treeline due to winds keeping alpine surfaces cool. NE below treeline got in on the action too in the happy chutes (see photo).

Weather: Few clouds. Warm temps below treeline. The alpine was very breezy with consistent moderate SW winds along with strong gusts.

Snowpack: Isolated 2-5 inch wind pockets on NE and E facing terrain near ridgeline. Previous tracks from yesterday in a steep alpine chute had been erased overnight due to wind-loading. Although the wind slabs were very small, it was still enough of an issue for us to avoid a very steep, exposed, slightly cross-loaded chute. We chose to descend a steep, planar north-facing slope away from any ribs or other features prone to cross-loading. There were no signs of instability on our descent.

The snow stayed dry on due north slopes. Below treeline NE-E facing slopes became moist by early afternoon as expected.

 

Photos:

Date of Observation: 03/27/2021
Name: Ian Havlick and Evan Ross

Zone: Southeast Mountains
Location: Whetstone and near Copper Lake
Aspect: East, South
Elevation: ATL

Avalanches: See photos
Fresh avalanche (appears to be a persistent slab) on an east aspect ATL of Mt. Whetstone, D2 in size.
Smaller wind slab avalanche on a south aspect above Copper Lake, D1.5 in size

Photos:

Date of Observation: 03/26/2021
Name: Zach Guy and Jack Caprio

Zone: Southeast Mountains
Location: Mt. Emmons
Aspect: North East, East
Elevation: 9,000 to 11,500′

Avalanches: One small wind slab likely ran naturally yesterday in Coon Basin (SE aspect, ATL).
Skier triggered a handful of shallow sluffs on steep, northerly terrain, about 6″ deep or less.
Weather: Afternoon tour brought overcast to broken skies. Brief convective pulses of moderate snowfall (S2) with an inch or so of accumulation, generally light winds with a few stronger gusts associated with the snow squalls.
Snowpack: Looking for feedback for persistent slabs in the type of terrain we’ve been warning about: shallow/previously avalanched, previously windloaded. Slabs are getting a little thicker now and we didn’t feel comfortable ski cutting or really getting onto suspect slopes to get a feel for how reactive they are. A few strategically placed pits along flanks or smaller terrain features produced a mix of propagating and non-propagating results on fist hard facet layers (1.5-2.0mm) on old bedsurfaces, generally 45 to 65 cm deep. The most concerning structures and a propagating result were on slopes where previous wind drifting created denser, harder layers above these buried facets, making for a more dramatic hardness change at the weak interface. Wind sheltered terrain held a softer slab and a less-distinct transition to these facets, with non-propagating results. Previous wind drifting and scarier structures were not apparent on the surface, but evident with probing or an understanding of local wind patterns. We avoided those types of slopes.

 

Photos:

Date of Observation: 03/26/2021
Name: Evan Ross

Zone: Southeast Mountains
Aspect: East, South East, South
Elevation: 9,300-12,300

Weather: Calm to light winds with a few stronger gusts transporting snow. Mostly cloudy sky with convective cells moving through and creating quick bursts of snowfall. Maybe an inch or two of new snow accumulation today, but it was settling quickly.

Snowpack: Potential wind slabs were small and from what I observed were really confined to right near the ridgeline or cross-loaded terrain features. Otherwise, the cream was getting thicker with periods of sun between the clouds. Similar to yesterday’s ob in Washington Gulch, there was about 4″ of recent snow accumulation down low and around 8 to 10″ up higher. No avalanche problems were observed outside of the potential wind-loaded terrain features. One snowpit at 11,300ft on a 33 degree south facing slope had about 8″ of new snow on top of a very stout crust with a matrix of other stout crusts and percolation columns below.

Date: 03/26/2021

Name: Jack Caprio

Zone: Crested Butte Backcountry

 

Consistent moisture throughout the week rewarded us with many pow days in the snow-favored areas of the zone. Check out the weekly summary to see how these storms impacted avalanche conditions.

Date of Observation: 03/27/2021
Name: Andrew Breibart

Zone: Southeast Mountains
Location: Washington Gulch-Coneys
Aspect: North East, East
Elevation: BTL

Avalanches: NA-poor visibility
Weather: Obscured skies with S1 and S2 snowfall. Calm. On the skin out, obstructed skies, calm and intermittent S-1 snowfall.
Snowpack: Supportive snowpack valley bottom to the ridge. 48-hour snow: 3 to 6 inches with 8 inches on the leeward side of the ridge line. New snow seems to be bonding to the last melt freeze crust. Triggered shallow storm sluff at the convex entrance to first bowl.

 

Date of Observation: 03/26/2021
Name: billy barr

Zone: Southeast Mountains

Weather: Very light, scattered dense snow Thursday, then light snow after midnight so the 24 hour total is 4″ new and 0.24″ of water. Snowpack is at 49½”, the deepest since mid February. Calm yesterday and so far today. High yesterday 33F, low today 18, current 19. Overcast with a very light snow.

Date of Observation: 03/25/2021
Name: Evan Ross

Zone: Southeast Mountains
Location: Coneys
Aspect: North East, East
Elevation: 9,000-11,000

Weather: Mostly Cloudy. Several nice burst of snow interspersed with sun and greenhouse conditions. Calm winds.

Snowpack: About 4″ of new snow down in the valley and about 8″ near the top of Coneys. New snow was well bonded to the supportable crust below. Hand pits wouldn’t pop anything above the crust and no signs to instability. Same results at ridgeline. Old tracks form yesterday were still visible off the highest point of Coneys. The new snow was definitely feeling the heat, but man the cream sure is surfing good.

Date of Observation: 03/24/2021
Name: Ian Havlick

Zone: Southeast Mountains
Location: Snodgrass Frontside
Aspect: North, North East, East
Elevation: 10,200-11,500

Avalanches: none
Weather: BKN moved to OVC with S-1 snow showers late afternoon. no accumulation. temperartures 20-28F. Mostly calm.
Snowpack: I dug 12 full profiles today for a CU researcher BTL snodgrass, N-E aspects. No stability tests as I was collecting density data in treed terrain, but still same poor structure, P-hard slab above 20-40cm 2-4mm F+ DH. has improved a bit from same locations dug 1 month ago, F- DH then, compared to F+ DH now, but still weak, and stiffer slab. General HS in areas dug between 11, 200 and 10,000 was 90-130cm.