Avalanches:

Weather: Broken skies with high thin clouds, calm and warm (air temps near freezing).

Snowpack: No sings of instability. Breakable crust (~5cm thick) covers all sun-exposed slopes. Surface snow faceting away and losing strength where not stiffened by recent winds. In steep terrain, multiple CT’s in different locations didn’t reveal any failures in the top 60cms. SH in this zone seems to have been flushed out when path ran at the beginning stages of the most recent trend of instability we had.

Avalanches: HS-N-R2-D2-O. Unknown trigger, possibly natural overnight or remote skier triggered this morning. Ran on slick P+ suncrust and small grained facets above. 150ft wide, running ~500 vertical feet. 34º slope, ESE facing Near/Above treeline.
Weather: Decreasing winds during the day, mild temperatures with high of 36º at 10,000ft. Rapid warm up this morning, but high clouds put a lid on high temps around 1400.
Snowpack: Continued wind loading, hard slabs throughout near and above treelike terrain. Pretty wind hammered. Hard slabs no deeper than 40cm in terrain travelled. HS 280-320cm.

gives and idea of wind texture at ridge top from 3 days of steady west winds

view from just above fracture line.

fracture line blown in, ski tracks visible in upper right corner.

Avalanches: Lots of skier triggered rollerballs on ESE aspects BTL; their first moistening of the week. No new avalanches observed.
Weather: Warm. Increasing thin clouds. Light winds below treeline.
Snowpack: Traveled in two areas near town that held similar snowpack structure to this observation. As we climbed above the inversion, slabs became less faceted, and the recent warming/settling has made the slabs denser and the surface hoar less reactive.  Slightly harder and more propagation in tests (see photos), but we ski cut about 5 steep slopes and couldn’t get anything to move or crack. These same types of slopes were very touchy last week, triggering was almost certain. It seems that instabilities are becoming more isolated, but greater potential for a slide breaking above a skier or a wider avalanche exists now at these locations. The persistent slab structure on SE aspects over the 1/19 interface is changing to a stack of thick crust over faceted snow. No concerns in the morning while the crusts were solidly frozen.  Weak layers on the surface: Small surface hoar and/or near surface facets on most open, shaded aspects. Large surface hoar on a few isolated north facing slopes.

NE aspect 10,000 ft.  32 cm, 4F slab over surface hoar.  ECTP11, SC.  Ski cut this slope where it rolled over to ~38 degrees with no result.

Rollerballs on Southeasterly aspects below treeline.

Avalanches: -One couch sized cornice fell off of an East aspect ATL today; didn’t trigger anything.
-A D1 wet loose looks like it ran in last couple days on a S BTL slope
-A number of crowns visible from last week’s avalanche cycle. See photos.
-A D2.5 (or larger?) debris pile below East face of Mineral Point, also from last week. Ran full track.
Weather: Strong winds, variable directions but mostly WNW. Light to moderate transport, mostly saltation, not loading. Mild temps. Few clouds to scattered clouds.
Snowpack: No signs of instability. 5 pits from BTL to ATL, generally with strong structure and no concerning results, even on a slope with buried surface hoar.  Ski pen is 10-15 cm BTL and 5 cm ATL. Slab depth down to 1/19 interface ranged from 50 cm BTL to 10-120 cm ATL, depending on wind patterns.  We ski cut and snowmobile cut a number of steep, suspect rollovers with no results on various aspects/elevations. Winds kept surfaces cool where we traveled; no wet loose concerns. Weak layers at the surface have been worked over by the wind. Here are the pit specifics
1. N aspect. 9,600 ft, in wind sheltered area. Could not ID any surface hoar. Q2 CTM and CTH on mid-storm DF’s. ECTN H on mid-storm DFs. Hard to ID 1/19 storm interface, but it was probably about 50 cm deep.
2. ESE aspect. 10,300 ft, in moderately wind affected area. No surface hoar, no PWL or crusts. Q2 CTM and CTH on DFs. Hard to ID 1/19 storm interface, but it was about 50 cm deep.
3. S aspect. 11,500 ft. 70 cm of 4F to 1F slab over Jan 19 crust. No obvious facets around crust. ECTN H BRK above crust.  HS over 400 cm.
4. NE aspect, 11,600 ft. 90 cm of slab over Jan 19 interface. No PWL. CTH Q2 on mid storm DFs
5. NNE aspect 9,600 ft. Adjacent to previous natural avalanche. Jan 19 SH buried 50 cm deep, well integrated into surrounding DFs. ECTN H BRK on SH. CTH Q2 on SH.

D1. SW aspect BTL

NNE aspect BTL. Adjacent to natural slide from last week.  Note the wind-damaged surface hoar on the surface.

South aspect ATL.

D1 wind slab, a few days old.

Surfaces are stiffened and roughened by winds at all elevations.

D2 NE aspect BTL. Profile #5 dug near this slope.

Recent D1 wet loose. S aspect BTL.

D1.5? NE aspect BTL

D2. NE aspect BTL

D2? NE aspect N/BTL

D2 NE aspect NTL

D1.5 NE aspect BTL

D2. East aspect BTL

Impressively far-running debris piles below Climax Chutes. These crowns reported last week.

Avalanches:
Weather:
Snowpack: See photos

E-ECTP18 SP (150cm column) 35cm deep 2-3 SH/NSF

E-ECTP13 SP (150cm column) 35cm deep 2-3 SH/NSF.  Slab was 1F above F hard weak layer and bed surface 1F.  (WSW FACING, 38º, 11,700FT)

SE aspect NTL. surface hoar present, below NC shooter, CT12 SP 35cm, with facet/crust combo below

Avalanches: No new avalanches observed.
Weather: Clear, light winds, and warming up.
Snowpack: Dug down to the storm interface in clearings on SE and SW aspects. SE had a fist hard slab sitting on a 2-3 cm melt freeze crust at the storm interface with no surface hoar present. It failed on mid slab instabilities as CTM SC but did not propagate during an ECT. With hard taps SE also failed on facets just below the crust but with irregular breaks. SW had 3-4, 1-2 cm melt freeze crusts in the top 50 cm with no surface hoar present. With medium to hard taps irregular failures occurred under the crusts.
A thin crust had formed at the surface on SE aspects and surface hoar was preserved at the surface through the afternoon. SW aspects were still wet at the surface during the afternoon and the surface hoar had been burned off.

Avalanches: SS-ASc-D1-I on a convex roll in a gully
SS-AMr-D1-I X2 on a small wind loaded roll.

South face of Teo had previously avalanched to its maximum trim line.
Weather: Clear skies, Calm winds with strong solar radiation and warm air temps.
Snowpack: South facing terrain in the brush creek zone has a noticeable shallower snow pack than the northerly portions of the compass. HS: 112cm. Snowpack on these south slopes was shallow due to a vary large avalanche during the early January natural cycle. Multiple large collapses observed on the up track accompanied by shooting cracks up to 30m away. Many of these collapses and cracks failed on the 1/19 interface 25cm down, while others were just the upper wind or sun crust shifting with the weight of a skier while it was softening under the sun. CT11 SC on the 19th interface failed on facets above a melt freeze crust. SW facing slope, 10,700′

At above treeline elevations the persistent slab problem was confined to wind loaded terrain features. The alpine terrain in the surrounding area looked very wind effected with similar terrain management necessary to avoid the avalanche problem.

On the shady side of the compass we observed snow depths hovering around 240cm. The 1/19th surface hoar interface was observed with a 40cm, fist to 4f slab sitting above. ECTN 11 NE aspect 10,500′. Below the surface hoar was a 4f to 1f mid pack.

Facets above a thin crust at the 19th interface were the weak layer in todays triggered slabs. The crust was often very aerated looking like in the shadow of this picture.

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Remotely triggered wind loaded slab failing on the 19th interface.

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10-12″ skier triggered wind loaded slab failing on the 1/19 interface.

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South face of Teo had previously avalanched to its maximum trim line. This is a poor picture for representation, but large trees were down on both sides of the valley at the previous maximum runout. Old Crown looked to have crossed the entire face. the aspen trees on the leading edges of those aspen groves in the middle of the path, had been push over.

This avalanche rose displays avalanche activity that we believe failed on the 1/19 persistent weak layer interface.  In most cases, this is on surface hoar, but on some cases on southerly aspects, this was on a crust/facet layer.  This is meant to show a general pattern , and there are some strong sampling biases to consider.  First, we did not have views of above treeline terrain 7 days while the weak layer was being buried and failing.  If there was evidence of natural avalanche activity above treeline on PWL,  it was likely brushed over by subsequent snow/winds before we set eyes on it. We also have very few due north and northwest paths near town, and a lot of human traffic is concentrated on NE and E aspects at lower elevations.  I think the take-home point here is that the action has been most concentrated near and below treeline, especially and NE/E aspects, but poor structures exist around the compass, and we have significantly less persistent slab data and lower confidence for above treeline slopes.  Size is generally larger on leeward aspects and higher elevations.  This rose does not include wind slabs that appeared to break in mid-storm layers and will be healing quickly now.  -Zach Guy

Persistent slab avalanche activity rose since January 19th

Avalanches:
Weather: Clear and calm, warming from ~0-20*F with strong solar radiation.
Snowpack: Several collapses (estimated 20-30m radius) in open meadows and low-angle aspen groves. Found the Jan 19th interface ~40cm down with surface hoar above a crust and facets below it. No snowpack tests. Presence of the surface hoar was enough information to know we wanted to avoid traveling on or under steep slopes.

A new layer of surface hoar was widespread but more pronounced in the valley bottom and a thin, soft crust was present on steep slopes at 0930 this morning.  By 1300, steep southerly slopes were moist again, but low-angle terrain still harbored unburied surface hoar despite the strong solar radiation.