Today expect ridgetop winds from the Northwest to steadily increase this afternoon ranging from 10-25mph with gusts reaching the 30-40’s mph. This wind direction can funnel through parts of Turnagin Pass from more of a Southerly direction. Be aware that loading may occur on a variety of aspects depending on which side of the road you are on. There is about 6 inches of snow available for transport and wind slabs are anticipated to grow to 10 -12” range. Watch for pillowed or drifted snow or where the snow may feel stiff and ”upside down,” and identify steep features like convexities or gullies where a shallow wind slab could knock you off our feet. The avalanche danger will depend on how much snow is being transported. If large plumes of blowing snow are observed, this could add stress to existing weak layers deeper in the pack, and make it easier to trigger a deeper more dangerous slab. More details in Secondary Concern below. Be prepared to change plans if you see any obvious signs of instability; shooting cracks, recent avalanches or collapsing “whumpfing” sounds.
Typical loading patterns of wind slabs
Skier triggered “sluff” on Corn Biscuits West face and a good example of the top 6″ of loose surface snow that is available for transport if winds pick up today.
Above 2000′ a widespread layer of buried surface hoar remains a concern on steep slopes, where triggering an avalanche 2-3’ deep has become stubborn due to a stabilizing snowpack. Relatively calm weather this week has allowed for folks to push further into the mountains with no reports of avalanche activity since last Saturday (2/18). However, increasing winds today may add additional stress and triggering a persistent slab avalanche could have high consequences. Triggering this avalanche will be more possible in steep terrain and in places where the snowpack is thinner – near rock bands or on more scoured features. Also, these slabs can break above you, and release after several tracks are on a slope. Be aware that snow pits and stability tests may not be representative of the actual slope you are trying to assess. A helpful way to think about this problem is to consider the consequences of a slope if it slides and identify and avoid terrain traps (gullies, cliffs, or trees below). Change your plans and avoid steep terrain should you see rapid loading due to blowing snow.
Deep Persistent Slab: We continue to find various layers of weak faceted snow and depth hoar near the bottom of the pack in certain areas. This includes Summit Lake zone, and some areas in Girdwood Valley and towards the Southern end of Turnagain near Johnson Pass. Similar to the problem above, these layers will be very tough to trigger, but a possibility remains in places with this structure.
Cornices: Winds today may add stress to already large cornices. Remember these unpredictable hazards can break farther back onto a ridge than expected and have the potential to trigger an avalanche on the slope below. Give cornices extra space and avoid being under them.
Loose snow avalanches: The top 6” of surface snow is loose and sluffs may be easy to initiate and fast moving on steep terrain features protected from the winds.
Glide avalanches: There is a new glide crack above the flats along Seattle Ridge, just looker’s left of the up-track and Repeat Offender slide path. Avoid hanging out under this crack and any others you may see.
A large cornice above Magnum’s SW face. Photo taken yesterday by Aleph Johnston-Bloom.
Yesterday skies were mostly sunny and temperatures reached the mid 30F’s during the heat of the day. Westerly winds were observed throughout our region averaging around 10mph with gusts in the 20’s mph. Low valley fog moved into Turnagain Arm towards Portage Valley late afternoon along with cooler temperatures overnight.
Today skies are expected to become cloudy causing valley fog to lift. There is a chance for light flurries. Northwest ridgetop winds (10-25mph) are expected to increase throughout the day. Sustained winds could reach the mid 20’s mph by mid afternoon, with gust in the 30-40’s mph. Temperatures will start drop by late evening, and may reach the single digits overnight.
Cold off shore flow is expected to continue over the next few days bringing more sustained ridge top winds and cold temps as high pressure settles in over interior Alaska. This pattern is expected to dominate Southcentral, AK for the next week. Today’s weather discussion warns; €œOld man winter is going to make a forceful return, reminding Alaskans that Spring is most definitely not here yet. €
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||26||0||0||65|
|Summit Lake (1400′)||26||0||0||31|
|Alyeska Mid (1700′)||27||0||0||60|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||25||NW||10||33|
|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.