Some Cracking

CB Avalanche Center2017-18 Observations

Location: Crested Butte Area
Date of Observation: 12/24/2017
Name: Karin Pocock

Subject: Some Cracking
Aspect: East
Elevation: 9,700-10,800

Avalanches:
Weather:
Snowpack: Some cracking no further than 1-2m from ski tips, some “whumpfing” on small convexities on slope that produced cracks, but nothing else.
Generally the HS is roughly 40-60cm. On average it’s 30(ish)cm of FC and small DH with roughly 15-20cm HST from the last 48hrs sitting on top of it. In sheltered areas the whole snowpack is relatively homogenous in resistance F through 4F-. In wind effected areas it’s super variable, stripped to the facets, pencil hard 1-3″ wind skin/windslab on the surface, or deeper HST of variable densities from wind effect.

Photos:

When will the slab form?

CB Avalanche Center2017-18 Observations

Location: Paradise Divid Area
Date of Observation: 12/24/2017
Name: Evan Ross

Subject: When will the slab form?
Aspect: North East, East
Elevation: 9,700-11,300

Weather: Fairly calm down in the valleys with some moderate westerly winds near treeline. Mostly clear sky became overcast in the early afternoon.
Snowpack: Still no persistent slab avalanche problem, even with 12″ of new snow since Wednesday night sitting on a weak faceted snowpack below. When will this upper snowpack become reactive on its weaker base? Thats the big and scary question. Even were the upper snowpack was stiffened by Saturdays wind event it was still mostly unreactive in this elevation ban. Found two very small wind-loaded pockets the broke on the interface between our two recent storms but not on the weak faceted snow below. HS in this area was about 60-70cm at 11,000ft.

Open slopes at any elevation, but mostly above treeline saw what looked like more snow stripped away by Saturdays wind event then loaded onto the slopes. Cross-loaded pockets behind tree fences or vertical ridges seemed to catch the most snow.

This observation is from one of the deeper parts of our forecast area. The vast majority of slopes observed on the way to this area have a very, very thin snowpack.

Photos:

Gothic Mountain Seen from the WSW

Cinnamon Mountain Seen from the Southeast.

Very Small windslab breaking between the two recent storm interfaces and not on the weak snowpack below. ENE aspect. 10,200ft.

Snodgrass Obs

CB Avalanche Center2017-18 Observations

Location: Crested Butte Area
Date of Observation: 12/24/2017
Name: AT

Subject: Snodgrass Obs
Aspect: North East, East
Elevation: 10,400

Avalanches:

None

Weather: Clear skies in AM becoming cloudier
Snowpack: On the uptrack wind deposited areas had as much as 12″ of storm snow on top of the faceted base. Wind scoured areas had in the 2-3″ range. On descent we produced some shooting cracks in an areas with over 12″ of wind deposited snow.

Photos:

Mountain Weather December 24th, 2017

CB Avalanche CenterWeather

Date: 12/24/2017

Well, it sure is nice to be back in the flow after a very dry November and December. Today we’ll see a break in the weather before the next fast and turbulent storm rolls in tonight. While today is a break in the weather its still going to be blustery up there, with west winds in the 20+mph range at 11,000ft. Cloud cover will begin increasing tonight and snow showers will intensify around midnight. This incoming storm will be similar to Saturdays, but with a little less wind. I hope Santa has himself a nice full face helmet and face shield for his adventures tonight because it’s going to be a blustery ride. Westerly winds should ease slightly for Christmas day and snow showers will taper as the day progresses. Northwest flow will take us through next week with some moisture and clouds around, but nothing too notable until maybe later in the week around Thursday.

  • Today

    High Temperature: 22
    Winds/Direction: 20-25 G35/W
    Sky Cover: Increasing clouds
    Irwin Snow: 0
    Elkton Snow: 0
    Friend’s Hut Snow: 0

  • Tonight

    Low Temperature: 15
    Winds/Direction: 10 to 20/W
    Sky Cover: Overcast
    Irwin Snow: 5 to 7
    Elkton Snow: 6 to 8
    Friend’s Hut Snow: 4 to 6

  • Tomorrow

    High Temperature: 24
    Winds/Direction: 10 to 30/W
    Sky Cover: Overcast
    Irwin Snow: 2 to 4
    Elkton Snow: 2 to 4
    Friend’s Hut Snow: 2 to 4

Athracites

CB Avalanche Center2017-18 Observations

Location: Kebler Pass Area
Date of Observation: 12/23/2017
Name: Eric Murrow

Subject: Athracites
Aspect: North, North East
Elevation: 10,000 – 11,500

Avalanches:

We triggered several small, very soft slabs (3 x SS-AS-R1-D1) they ran more or less like loose sloughs. Propagation was only about 20 feet. I was not able to investigate crowns but they appeared to be around 6 inches deep, likely failing within the new snow (see photo). One other triggered slide (I couldn’t see crown) was believed to be closer to 12 inches deep as described by person that released it.

Weather: Overcast all day. Light snow most of the day, s-1. A short period, about 10am to noon, of s1,s2 snowfall rates. Winds were light for most of the day with very little transport. At around 330pm, the winds noticeably ramped up to 20+mph. Winds out of NW. At 445pm winds were actively blowing snow out of seven bowl and into upper parts of east bowl. Snowmos accumulated 3.5” of snow from 10:15 to 4:45.
Snowpack: New snow accumulations since Wednesday night were between 8 and 12 inches. New snow had yet to form a slab. Did notice a slight storm density change about 5 inches down.

Photos:

Valley bottom ob.

CB Avalanche Center2017-18 Observations

Location: Crested Butte Area. Washington Cultch
Date of Observation: 12/23/2017
Name: Evan Ross

Subject: Valley bottom ob.
Aspect: East
Elevation: 9,600-10,000

Weather: Obscured Sky. Snowing mostly S1. About 2-3″ accumulation between 11am and 3pm. Some gusty down valley winds but we were mostly protected by some trees.
Snowpack: Was only on sub 30 degree low angle terrain in the valley bottom. About 6″ of new snow accumulation since Thursday. Hand pits showed the top couple inches of new snow moving onto of Thursdays snow and not on the old snow/faceted interface.. Though these obs were from so low in the valley and there really wasn’t any slab yet for notable results. HS about 40cm.

Photos:

Mountain Weather

CB Avalanche CenterWeather

Date: 12/23/2017

The upper jet nosing into Colorado will carry yet another storm this morning, with good precipitation spurred by the upper level jet support slamming into the Rockies and adding good orographic lift. Unlike our last storm, todays weather will be accompanied by warmer temperatures, and much more wind, especially near and above treeline. Wind will begin to really howl starting early afternoon and build through this afternoon. Snowfall accumulations look to be in the 3-6” range on most models today, with more on the way tomorrow night. Tomorrow’s storm will add another boost of snowfall to bring snow totals potentially into the double digits. We will keep focused on today’s storm and wait for this afternoon’s model run to get excited.

  • Today

    High Temperature: 25
    Winds/Direction: 15-30mph G60/W
    Sky Cover: Overcast
    Irwin Snow: 4-7″
    Elkton Snow: 4-7″
    Friend’s Hut Snow: 2-4″

  • Tonight

    Low Temperature: 7
    Winds/Direction: 10-20/WNW
    Sky Cover: Decreasing clouds
    Irwin Snow: 0-2″
    Elkton Snow: 0-2″
    Friend’s Hut Snow: 0-2″

  • Tomorrow

    High Temperature: 26
    Winds/Direction: 10-20/W
    Sky Cover: Mostly Clear
    Irwin Snow: 0
    Elkton Snow: 0
    Friend’s Hut Snow: 0

More sand in the Sandbox

CB Avalanche Center2017-18 Observations

Location: Paradise Divide Area
Date of Observation: 12/22/2017
Name: Evan Ross

Subject: More sand in the Sandbox
Aspect: North, North East, East, South
Elevation: 9,700-12,300

Weather: Gusting moderate winds from the northwest were blowing snow around above treeline. A few swirling gusts at lower elevations otherwise mostly calm winds. Few clouds.
Snowpack: Couldn’t buy an avalanche, even with one of those BitCoins. Yesterday’s new snow was very soft and lacked any cohesion to form slabs. Very continental snowpack. Maybe that snow fell with such cold temperatures, then the sky cleared overnight and the 6″ HST at 11,000ft just headed down the faceting train and never got a chance to strengthen into a slab. Kind of like sprinkling some powdered sugar on top of the large-grained sugar. It’s still a surgery sandbox. This was the snowpack structure on North and Northeast facing slopes above 10,500ft up to an observed 11,500ft. Below that elevation ban, there is very little snow. The crust that was observed in this observation was only present on easterly facing slopes in this area. Southerly facing slopes in the area were just a little new snow on the ground.

At ridgeline, most of the recent new snow had already been transported. This snow had been loaded onto easterly facing slopes right at ridgeline, and further downslope on cross-loaded terrain features. Drifts up to 2 feet deep could be found, but were very narrow and didn’t extend downslope very far. These drifts were also fist hard and didn’t want to budge on the old snow surface. Probably due to lack of cohesion or just small square footage size. Northeasterly and north facing slopes were blown back to the old snow surface. Cross-loaded terrain features on these north to northeast facing slopes would maybe be more reactive then what I observed?

In the end, went searching for an avalanche problem in some of the most suspect areas and couldn’t find one. Windslabs would have been the only terrain management, but didn’t find any that were reactive. When will more widespread slabs form is the big question.

Photos:

Protected NNE facing slope at 10,800ft. The new snow may look more white, but it was still just sugar on sugar. When ever that new snow forms a slab it will be ugly, but it hasn’t happened yet.

Windslab? They were all so soft on easterly facing terrain and not showing any sings of bugging on the old snow surface. Weak layers below but not nearly enough weight to collapse them. Right near rigeline these drifts were up to 2 feet deep. Most of the new snow in the alpine was already blown around by the winds.

North Aspect at 12,000ft. Mostly blown back to old snow surfaces. Thats a rock track sliding down the slick old snow.

 

Cross-loaded terrain features on north and northeast facing terrain may have been more suspect. These very soft slabs would have been managed like windslab characteristics.

Most of the new snow had already been transported above treeline.

Example of easterly aspect below 10,200ft. This thin snowpack coverage didn’t change between the Crested Butte Area or the Paradise divide Area. Northeasterly facing slops didn’t have much more coverage.

Looking at the 9,500ft to 11,400ft elevation ban generally facing Northeast, on Schuylkill Ride in the more snow favored Paradise Divide area. Still very thin snow coverage.

Mountain Weather

CB Avalanche CenterWeather

Date: 12/22/2017

Just as I was beginning to think we had all been naughty, and this storm was our equivalent to coal in the ol’ stocking…the stalled cold front limped its way over the West Elks and gave us the much anticipated snowfall. Look for a few clouds to hang over the high peaks this morning, before that cold, dry arctic air briefly takes hold before high and mid level clouds stream into the central mountains ahead of another storm set to reach Colorado late tonight, and last through tomorrow. Winds should remain light this morning, then steadily increase throughout the afternoon. Temperatures will struggle to break the mid teens, especially at higher elevations. There remains some uncertainty with the trajectory of this storm arriving tonight, forecasted to impact the northern mountains a bit more, but a shift of the jet south will tilt more favored snow totals our direction. Yet another storm is lining up for Rudolph’s voyage Christmas Eve. Maybe we have been good after all?

  • Today

    High Temperature: 20
    Winds/Direction: 5-15/WNW
    Sky Cover: Decreasing clouds
    Irwin Snow: 0″
    Elkton Snow: 0″
    Friend’s Hut Snow: 0″

  • Tonight

    Low Temperature: 10
    Winds/Direction: 10-20/WNW
    Sky Cover: Increasing clouds
    Irwin Snow: 0-1″
    Elkton Snow: 0-1″
    Friend’s Hut Snow: 0″

  • Tomorrow

    High Temperature: 25
    Winds/Direction: 15-25/W
    Sky Cover: Overcast
    Irwin Snow: 4-6″
    Elkton Snow: 4-6″
    Friend’s Hut Snow: 2-4″

Opa Hut Storm Observation

CB Avalanche Center2017-18 Observations

Location: Cement Creek Area
Date of Observation: 12/21/2017
Name: Morgan Boyles

Subject: Opa Hut Storm Observation
Aspect: North East, East
Elevation: 10-11,500

Avalanches:

none

Weather: intermittent bands of S-1 to S2 with overcast to broken skies. winds were calm to light.  10cm new snow.

Snowpack: skied east facing, 30º slopes 1mi north of Opas Hut, HS 30-90cm, mix of supportive, breakable and soft shaded facet skiing. 1 section of isolated cracking on NE facing slope on a slick melt-freeze crust. Good stability.