Christmas night’s foot of low-density snow greeted many backcountry skiers at Turnagain Pass yesterday. The snow was quite light and though it was sitting on a weak layer, was too loose to act like and slab in popular areas with little wind effect. Despite this, a group skiing on Tincan did trigger this very small wind slab avalanche from a distance. With such poor visibility and folks staying away from the higher windloaded terrain, this was the only avalanche we know of.
Small and very soft wind slab avalanche, remotely triggered by skiers descending from the higher terrain under Common Bowl and into the Tincan Trees yesterday 12/26. Credit: Billy Finley
|Signal Word||Size (D scale)||Simple Descriptor|
|Small||1||Unlikely to bury a person|
|Large||2||Can bury a person|
|Very Large||3||Can destroy a house|
|Historic||4 & 5||Can destroy part or all of a village|
For today, any fresh wind slab and/or lingering wind slabs from the past two days are all suspect for being unstable. This is due to either a layer of buried surface hoar or simply very loose weak snow that sits right under the slabs. High elevation slopes with the most wind effect are the most concerning.
If skies stay clear enough for travel to these higher slopes, keep a close lookout for windloading and areas where the top foot of snow is stiffer than the snow underneath. Any whumpfing or cracks that shoot out in the snow around are a clear sign that layer of snow could avalanche.
Video from Tincan 12/26, link HERE.
There are actually two layers of buried surface hoar, one buried on the Solstice and one on Christmas. Of these, the lower one (the Solstice Buried Surface Hoar) has been the most prevalent and could start causing us more grief in the days to come. So far, much of the 12-14″ of snow above it has not been consolidated enough to form a slab, once it does, we could start seeing avalanches in popular areas that we did not see yesterday.
Sluffs: The very cold temperatures that moved in last night should keep much of the snow above these weak layers loose in areas out of the wind. Watch your sluff on the steeper slopes.
Cornices: Natural cornice falls were noted during the Christmas night storm as well as a few from yesterday. These are worth giving a wide berth as they could be teetering on the balance.
Mid elevations and more snow on the way: A heads up that with warming temperatures and more snow on the way, even slopes in the trees could become unstable and dangerous in the days to come. This is all due to that pesky solstice weak layer that is just waiting for a consolidated slab to start producing avalanches…
Aleph points out the Solstice Buried Surface Hoar sitting on a crust. The layer is under 14″ of loose snow at 1,200′, which is just above the road.
New snow and wind is likely filling in glide cracks throughout the region and they could be more difficult to see. Despite this, keep a close look out for them and remember glide avalanches are very unpredictable and it’s not a good idea to linger under cracks.
Yesterday: Cloudy and obscured skies were over the region. No snow has fallen in the past 24 hours. Ridgetop westerly winds were moderate (5-15mph) and in bringing in very cold air. Temperatures have been declining and sit this morning in the single digits and minus single digits at all elevations.
Today: Mostly clear skies should transition to high clouds in the afternoon as the next wave of precipitation moves in tonight. Snowfall should begin around 6pm with 4-8″ forecast to fall tonight. Ridgetop winds will being a shift to an easterly direction and blow ~5-15mph today before increasing tonight up to 20-30mph with stronger gusts. Temperatures will remain cold, near 0F today before slightly increasing tonight.
Tomorrow: Snowfall should continue through Saturday with an additional 4″ or so falling before the system pushes out in the evening. Ridgetop winds look to remain gusty, swing back westerly and blow in the 15-30mph range. Temperatures should bump back up the teens and 20F before the next front looks to swing in on Sunday evening bringing another round of precipitation.
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||11||0||0||36|
|Summit Lake (1400′)||9||0||0||10|
|Alyeska Mid (1700′)||11||trace||trace||27|
RIDGETOP 24-hour data (6am – 6am)
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||N/A*||N/A*||N/A*||N/A*|
*Rime has covered the wind sensor on Seattle Ridge.
|05/06/20||Turnagain||Avalanche: Pastoral Peak, north face||Andy Duenow|
|04/10/20||Turnagain||Avalanche: Wolverine||Mike Records|
|04/10/20||Turnagain||Observation: Eddies lookers right shoulder||Matt Yoder|
|04/09/20||Turnagain||Observation: Bench Peak||Mike Records|
|04/04/20||Turnagain||Observation: Pete’s North||Anonymous|
|03/26/20||Turnagain||Avalanche: Tincan – Proper (SW facing)||CNFAIC Staff|
|03/26/20||Turnagain||Avalanche: Seattle Ridge||W Wagner Forecaster|
|03/25/20||Turnagain||Avalanche: Sunburst Uptrack @ 2000′||J. Boisvert|
|03/24/20||Turnagain||Observation: Turnagain – Road Observations||W Wagner Forecaster|
Status of riding areas across the Chugach NF is managed by the Glacier and Seward Ranger Districts, not avalanche center staff. Riding area information is posted as a public service to our users and updated based on snow depth and snow density to prevent resource damage at trailhead locations. Riding area questions contact: firstname.lastname@example.org
|Area||Status||Weather & Riding Conditions|
This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area. This advisory does not apply to highways, railroads or operating ski areas.