If this is your first day reading the advisory this winter it is important to know that deep slab avalanches have been a concern in the advisory now for two weeks. If you have been following along all season we are not trying sound like a broken record but the message is the same. This snow pack set-up continues to warrant elevated caution and respect. It is a high consequence avalanche problem that is impossible to outsmart. The snowpack recipe for deep slab avalanches has been found in the upper elevations of our forecast zone, above 3000’ on slopes that did not avalanche during the early December storm cycle. The snowpack ranges from 3-5+’ thick and is sitting on weak basal facets. Observations over the last few weeks indicate this poor structure is widespread across our region in the alpine elevations.
When dealing with a deep slab avalanche problem, keep in mind:
Obvious clues like ‘whumpfing’ and shooting cracks may not be present until it is too late. Evaluate snow and terrain very carefully and steer clear of large loaded slopes.
Pastoral avalanche that occurred on December 20th and was remotely triggered. Photo: Trip Kinney
Be suspect of steep unsupported slopes that have a fat, smooth, pillow-type shape to them. Strong Easterly winds over the weekend changed the surface conditions of our forecast zone, creating hard wind slabs on leeward features. The wind slabs may be farther down slope due to the high wind speeds or only found on one side of gully features due to cross loading. Any wind slabs today will be hard and supportable (to a skiers weight), they could be stubborn to initiate and may lure a skier well onto a slope before it fails. Listen for that hollow, drum-like sound below your skis or use a pole to probe for a hard snow over weak snow set up. These slabs could be as thick as 1-2’ deep in upper elevations and if triggered in the alpine have the potential to initiate a much larger and more dangerous deep slab avalanche.
Natural wind slabs on Seattle Ridge that happened sometime during the wind event just prior to Christmas.
Yesterday was mostly clear and sunny with valley fog. There was a temperature inversion. Temperatures were in the low 20Fs to teens at upper elevations and teens in the valleys. Overnight temperatures dropped down into the single digits in the valleys. Winds were light and variable.
Today will be similar with valley fog and sunshine above. Temperatures will be in the low to mid 20Fs and winds will be light and variable. Temperatures will be in the teens overnight and winds will remain light.
Tomorrow also looks like it will be mostly sunny becoming cloudy overnight into Friday. There is a chance of snow showers over the weekend.
*Center Ridge SNOTEL is reporting erroneous temperature data. See Turnagain Pass DOT weather station for accurate temperature at 1000′.
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||*23||0||0||29|
|Summit Lake (1400′)||7||0||0||11|
|Alyeska Mid (1700′)||18||0||0||26|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||18||Varible||3||6|
|04/19/21||Turnagain||Avalanche: Triangle, Seattle creek||Will Morrison|
|04/18/21||Turnagain||Avalanche: Turnagain Pass Road Obs||Andy Moderow|
|04/18/21||Turnagain||Observation: Seattle Ridge, approximately 300 yards south of the up track||Brent Byrne|
|04/17/21||Turnagain||Avalanche: Road obs||Johnston-Bloom / Moderow Forecaster|
|04/16/21||Turnagain||Avalanche: Seattle Ridge||Wendy Wagner Forecaster|
|04/16/21||Turnagain||Avalanche: Turnagain Pass, non-motorized side seen from Seattle Ridge||CNFAIC Staff Forecaster|
|04/16/21||Turnagain||Observation: Sunburst||Lance breeding|
|04/15/21||Turnagain||Observation: Tincan||Schauer/ Rothman Forecaster|
|04/13/21||Turnagain||Observation: Turnagain Pass Road Obs||A Schauer Forecaster|
|04/12/21||Turnagain||Observation: Tincan||Johnston-Bloom / Latosuo 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.