Date of Observation: 03/16/2021
Name: billy barr
Zone: Southeast Mountains
Weather: Probably the most snow we received during this whole storm was from 5 to before 7 a.m. this morning with 2″ new, but then only 0.11″ of water with it. The 24 hour total was 3″ new with 0.15″ of water and snow pack is at 44½” deep. Mild with the high 36F, low 11 and current 18. Currently cloudy with light snow and no wind.
Date of Observation: 03/15/2021
Name: Zach Kinler
Zone: Northwest Mountains
Location: Kebler Pass area
Aspect: North, North East
Elevation: 9,000′-11,200′
Avalanches: No new avalanches observed skies were overcast with limited vis into the surrounding terrain.
Weather: OVC, sporadic light snow showers throughout the day amounted to little additional accumulation. Winds were calm below tree line and very light near tree line. Temps remained below freezing.
Snowpack: Measured 8″ of new snow overnight which was very low density, around 3%-4%. 2 day HST in this zone is now 22″/~1.25″ SWE. Hand shear tests were breaking above the new/old interface at a density change. No signs of instability were noted while skiing slopes up to 38 degrees in this terrain. Minor cracking was observed in the deepest drifts near tree line. No results ski cutting slopes that produced small slab avalanches yesterday in this terrain as storm and wind slab instabilities are settling out.
Date of Observation: 03/15/2021
Name: Evan Ross
Zone: Northwest Mountains
Location: Washington Gulch
Aspect: All
Elevation: 9,000-11,300ft
Avalanches: Had some fairly good views of lots of terrain and didn’t note any new avalanches. Still lots of old avalanches from last month waiting to get buried.
Weather: Clouds cleared a bit throughout the day. Periods of light snowfall during the day put down some nice goose feathers. Didn’t see much for drifting during periods of visibility, but also didn’t spend a lot of time in exposed terrain.
Snowpack: Touched all the aspects, but primarily traveled on northerly facing slopes below treeline where the best riding was. At 11,000ft and on shaded slopes, storm totals were currently settled to about 6″. On sunny slopes or at lower elevations storm totals were 1 to 4″ on average. So Kebler clearly got a bit more snow out of this storm. We didn’t encounter any new avalanche problems.
In the late afternoon, I spent a little time at an 11,300ft near treeline point. Here I found isolated drifts up to 10″. Hunting around for a more notable snowpack ob didn’t produce in that area. The new snow was getting thicker and/or baking in on East, South, SW at this location.
Date of Observation: 03/14/2021
Name: Eric Murrow
Zone: Northwest Mountains
Location: Anthracites
Aspect: North, North East, East, South East, South
Elevation: 9,200′ – 11,300′
Avalanches: Intentionally trigged several D1 loose avalanches on south-facing near treeline slopes – ran on 4-7cm knife hard melt/freeze crust.
Remotely triggered a slab on an east aspect at 11,200′ from low-angle terrain above – never got vis below the convex roll so uncertain if it propagated further as it ran downhill.
Weather: Overcast skies, moderate northwesterly winds, generally S1 snowfall from 11am – 4pm. Hard to say how much it snowed while out as the storm snow was settling as it accumulated.
Snowpack: Midday measured around 12″ new snow w/ .9″SWE at 10,600′. Observed a midstorm density change in Shovel Tilt Tests. Stomped around on several small shaded test slopes and several steep sunny slopes with almost no cracking other than some ski length cracks in shallow drifts on leeward southerly features. While walking above a steep east-facing slope, looking for a facet/crust combination underneath the new snow, I was able to remotely trigger a convex roll below me. I was not able to get to the crown and never got a good view of the terrain below, but probing above the crown confirmed a soft, collapsible crust beneath the storm snow (similar to obs from Axtel and Snodgrass earlier in the week). I suspect due to wind, I missed the audible collapse of the crust as I skied above. The crown appeared to be slightly drifted where it failed. Snow felt noticeably thicker throughout the day as it settled.
Second-hand reports from Axtel stated 8″ new snow with some loose snow sluffing, and one small triggered slab in an open area below treeline.
Photos:
Date of Observation: 03/14/2021
Name: Zach Kinler
Zone: Northwest Mountains
Aspect: North, North East
Elevation: 10,000-11,200
Avalanches: Triggered 2 small slabs both running within the new snow on drifted features near and below tree line. Crowns averaged 6-10″.
Weather: Overcast, S1-S2 snow showers with 2′ accumulation during the day. Cold with moderate NW winds in large open areas below tree line and all near tree line locations.
Snowpack: HST 14″ at 3:30 pm. Measured 12″ with .8″ SWE at 10:00. Overnight snowfall was low density at around 6%. Density increased slightly through the day but remained quite enjoyable. Minor cracking was observed only in spots where winds were able to drift snow. Cracking and small slabs were breaking within the new snow in this location. Open slopes near tree line in this terrain were getting cross-loaded by moderate WNW winds throughout the day.
Date of Observation: 03/12/2021
Name: Sam Eller
Zone: Northwest Mountains
Location: The Playground and Ohio Pass
Aspect: North, South, South West
Elevation: 10,000
Avalanches: Knocked off a small wind slab that had loaded low into one of the chutes in the playground. Observed a large wet slab that appeared to be only a few days old.
Weather: Warm but strong south winds were keeping slopes from wetting extensively. Winds were blowing up the basin and loading in the north chutes from the bottom as well as other aspects.
Snowpack: Dug several handpits on the the way up north facing where there was a small facet layer 30cm down under the new March snow. South facing was wetting in the new snow but crust underneath was supportive all day. Wind affect on most aspects after midday.
Photos:
Date of Observation: 03/12/2021
Author: Jared Berman, Zach Guy
Zone: Crested Butte Backcountry
This week we saw many different avalanche types from wet slabs to dry slabs. Learn all about why this happened and what this means down the road in this week’s Weekly Summary.
Date of Observation: 03/11/2021
Name: Jack Caprio, Evan Ross, Zach Kinler
Zone: Northwest Mountains
Location: Skooks
Aspect: North, North East, East
Elevation: 9,000-11,400
Avalanches: No new avalanches observed.
Near ridge line, we initiated collapses along with radiating cracks on recently loaded NE to E facing start zones.
Weather: Broken skies for most of the day. Periods of S-1 snowfall. Light winds.
Snowpack: We went hunting for information on our recently buried March weak layer ahead of this weekends storm. Below tree line, the weak layer is buried by 4” of recent snow. On easterly facing slopes around 9.5k, the interface consisted of a soft 2” thick MF crust resting on top of 1-2 mm facets. Quick shovel shear tests at this site produced easy failure results just below the crust. As the compass tilted north-east the crust became softer and weaker. On due north slopes the interface consisted of 1-2 mm near-surface facets. As we gained elevation we continued trying shovel shear tests that produced failure both above and below the crust. We saw some cracking and got a couple collapses on leeward slopes just below ridgeline where 12″ or more of new snow had drifted over the weak new/old interface.
We also tested the 12/10 interface at a deeper, near tree line site. At this site, the 12/10 interface was buried 110 cms below the surface and consisted of 4F 2-4 mm DH. A pencil hard 110 cm slab is resting on top of this interface at this location. A PST test resulted in unlikely propagating results (80/110 END down 110 cm). The 12/10 depth hoar was moist and seemed to be showing signs of rounding and sintering.
Date of Observation: 03/10/2021
Name: Kinler, Caprio, Ross
Zone: Northwest Mountains
Location: Kebler Pass
Aspect: North East, East
Elevation: 9,500ft to 11,900ft
Avalanches: Remotely triggered one small soft slab from about 10 feet away. Crown estimated to have averaged about 8″ thick, failing in faceted snow between a pair of soft crusts. Steep East aspect 11,600ft. While small in size, this avalanche ran about 1,200 feet through steep terrain. Skier triggered a couple small loose snow avalanches that were mostly stubborn to trigger on steep northerly facing slopes below treeline.
Weather: Snowfall tapered off for most of the day, before starting to pick back up again around 5pm. Mostly light to moderate winds were we traveled. Clearly stronger winds at higher elevations and plumes of some of the high peaks.
Snowpack: We mostly traveled on northerly facing slopes below treeline. At valley bottom,HST at 4:30 was 5″ settled with .45″ SWE(9% density) Here, the new snow was a bit thick. Loose snow avalanches where the main concern, though they were a bit stubborn to trigger on steep 40 degree slopes. A couple interfaces of small facets were observable in the upper 20cm’s of the snowpack. Something to keep an eye on down the road.
Date of Observation: 03/08/2021
Name: Zach Guy and Jack Caprio
Zone: Northwest Mountains
Location: Mt. Emmons
Aspect: North East, South East
Elevation: 9500-12200′
Avalanches: Nothing new
Weather: Light snowfall, about 1″ of accumulation, moderate westerly winds with light transport at ridgetop, and overcast skies until about 3:30 p.m. Skies started clearing after that.
Snowpack: Snow surfaces remained dry at all elevations on northerly aspects, with some minor facet sluffing at lower elevations.
On solar slopes, surface crusts remained frozen and supportive on wind-exposed slopes near and above treeline. Below treeline, the crust was punchy (a couple inches thick) midday and thawed by this evening. Boot pen was about shin-deep into wet grains. We dug one pit on a southeast aspect at 10,400′ (see photo). The snowpack was wet throughout; we got moderate, propagating results on wet facets in the lower snowpack. No obvious signs of instability such as collapses, rollerballs, etc.
Photos:
