Mountain Weather 12/13/15

CB Avalanche CenterWeather

Date: 12/13/2015

We’ll see low level clouds burn off through the day under a fast moving transitory ridge. The next system has already moved onshore over California. A deepening trough bring snowfall back to our mountains starting midday on Monday. Flow will initially be out of the southwest, with the best jet support staying to our south. We should see a few inches during the day on Monday. Cold front passage and more favorable flow arrive Monday evening into Tuesday as the trough closes off and passes overhead. 5″ to 10″ looks like a safe bet by the time this system exits on Tuesday night.

Conradical

CB Avalanche Center2015-16 Observations

Location: Crested Butte Area
Date of Observation: 12/12/2015
Name: than
Subject: Conradical
Aspect: North East
Elevation: BTL

Avalanches: none
Weather: warm, cloudy, calm, intermittent light snow
Snowpack: Beat. Pockets of sugar between frozen old tracks. 3 inches of new. Reminded me of a dead beaver I found last summer (see photo).

beaver-on-a-stick

Poverty Gulch Dec. 12

CB Avalanche Center2015-16 Observations

Location: Paradise Divide Area
Date of Observation: 12/12/2015
Name: Dustin Eldridge
Subject: Poverty Gulch Dec. 12
Aspect: North, North West
Elevation: 9,400- 11,000

Avalanches: Facet sluffs seemed to be more of a concern than the new snow. We released two facet sluffs, one on the uphill and one on the way down (up to 40 deg slope). The sluffs did not break below the new snow interface except in areas where the skier broke the slab near the top of the pack.
Weather: Light snow was falling on and off throughout the morning with little to no accumulation through 1 pm. Calm with no evidence of wind during the storm.
Snowpack: Around 3 inches of new snow, very similar to what was seen in town. Snowpack near treeline was around 50-70 cm with a persistent slab structure. The slab was approx. 20-30cm with another layer of faceting crystals below and about 10-20 cm of large grain faceted crystals (looked close to fully developed I believe) below that.

Irwin snow obs

CB Avalanche Center2015-16 Observations

Location: Kebler Pass Area
Date of Observation: 12/12/2015
Name: Zach Guy
Subject: Irwin snow obs
Aspect: West
Elevation: Near treeline

Avalanches: We remotely triggered one small slide, about 30 feet wide, from about 75 feet away. It was a thin hardslab (3″ to 8″ thick) over fist hard facets, which gouged down deeper after failure. HS-ASr-R1-D1-O
Weather: Very light to no snowfall through the day, with no accumulation. Calm winds. Overcast skies.
Snowpack: 2″ to 3″ of new snow was a non-issue for storm instabilities. No snow transport. On westerly aspects near treeline, the snowpack was shallow and mostly faceted (2-3mm, Fist hard), with thin hardslabs or windcrusts capping the snowpack below the new snow in some of the more wind affected areas. We consistently found clean shears and propagating test results at this interface between 1F wind packed rounds and F facets, generally 10-20 cm deep. A few deeper pockets in isolated drifts.

IMG_5350

Mountain Weather 12/12/15

CB Avalanche CenterWeather

Date: 12/12/2015

Yesterday’s forecasted storm took some time out of its schedule to slow down and remind weather forecasters who’s boss. No matter, snow is still on its way with snowfall rates picking up at about 3am this morning. Just much later then forecasted yesterday. The sun will rise this morning with a couple inches of new snow on the ground while the heavier precipitation rates will be during the first half of Saturday, mostly before 11am. Some models are still excited for today’s total snowfall with .8” SWE by 5pm. However the Low Pressure trough is currently digging further south than anticipated which is leading to cutting those total snowfall numbers slightly. A weak ridge will be moving into our area this evening leading to a drying trend for Sunday. Winds will be light through today before picking up from the north tonight.

Snodgrass Study Plot

CB Avalanche Center2015-16 Observations, Snow Profiles

Location: Crested Butte Area
Date of Observation: 12/11/2015
Name: Zach Guy and Jimmy Buchanan
Subject: Snodgrass Study Plot
Aspect: North East
Elevation: 9,760



Weather: See profile. No precip yet.
Snowpack: See profile. No signs of instability.

profile-2

Mountain Weather 12/11/15

CB Avalanche CenterWeather

Date: 12/11/2015

Just when we didn’t think it would ever snow again, the weather forecasts have some interesting changes in store through the start of next week. Currently there is a low pressure trough approaching from the west and a cold front stalling over northern Colorado. A number of weather factors are combining to produce enhanced snowfall numbers north of I-70 and I don’t know if it’s the weather forecasters that are more exited or those locals.

For our area we’ll have to mostly really on orographic snowfall from southwest flow for today’s accumulations. So we should pick up a few inches mainly west of Crested Butte today with continued strong winds from the Southwest. Late this afternoon and tonight we’ll get our share of enhanced snowfall before things start to quiet down as Saturday progresses. Winds will finally start decreasing also on Saturday as the low pressure trough moves over Colorado. A weak high pressure ridge will build as the trough heads east before the next system moves in early next week.

Mountain Weather 12/10/15

CB Avalanche CenterWeather

Date: 12/10/2015

High level clouds and winds will increase under westerly flow ahead of an incoming Pacific system bringing deep moisture. Favorable jet dynamics and a cold front are forecasted to stall over northwest Colorado, leaving us out of the bulls-eye for Friday’s snowfall. The influences of the jet won’t miss us though, with strong to extreme alpine winds at the front end of this system. The cold front then pivots through the Elk Mountains on Friday night, boosting snowfall and pushing our snowfall totals closer to a foot on Saturday in favored locations. A transitory ridge follows behind on Sunday, bringing a lull in weather before another system arrives Monday, bringing continued snowfall.

SH on the snow surface

CB Avalanche Center2015-16 Observations

Location: Kebler Pass Area
Date of Observation: 12/09/2015
Name: Ben Pritchett
Subject: SH on the snow surface
Aspect: North, South
Elevation: near and below treeline

Snowpack: Surface Hoar widespread in Anthracites. 2-3mm SH on the sunnies, 5-7mm SH on the shadies. Still barely supportive on lower angled slopes; facet wallowing on steeper terrain. The Dec 10th or 11th interface will likely be a player for a while to come!

Ruby Range Obs

CB Avalanche Center2015-16 Observations

Location: Kebler Pass Area
Date of Observation: 12/08/2015
Name: Ian Havlick
Subject: Ruby Range Obs
Aspect: North, North East, East, South East, South
Elevation: 10-13,000

Avalanches: 2 recent cornice falls off Owen and Purple ridgelines. No avalanches triggered from these events. Dropped a fairly large cornice and pryed off 10′ wide, 10″ windslab.
Weather: Low ceilings, flurries disapated into broken then partly cloudy skies as day went on. Steady 10-20mph west winds at ridgetop.
Snowpack: Generally stable conditions, even in steep and extreme terrain. no snow transport. Pits and probing indicated gradually increasing hand hardness with depth, HS 10-11000 averaged about 70cm, smow in NE cirque of Mount Owen averaged 150-300cm. One pit, CTN @ 11,000, E-facing, 35º.

Cornices on ridgetop are tenuous and rotting out at roots.