The late January onslaught of rain and high temps was followed by a period of clear and cold weather. At the tail end of this January storm a small amount of snow fell in the higher elevations. That thin layer of snow sat on a stout slick crust for almost ten days. During that time this layer grew weak. Between Feb 7th and today over 36” of snow has fallen on top of this weak layer in the higher elevations. In areas where this weak layer exists, mainly above 3,000’ and in some places above 2,000′, the potential for slabs up to 3’ in depth could release from the weight of a person.
This issue is a tricky one to detect. Because the distribution of this weak layer is not uniform, it is difficult to know with confidence whether that weak layer is lurking below you or not. It should be assumed that this combo is present above 3,000’. This problem reared its ugly head yesterday with multiple parties reporting remotely triggered avalanches throughout the forecast area. Click for Eddie’s avalanche, Twin Peaks avalanche & Tenderfoot (Summit Lake area) avalanche.
The best way to manage this problem today is to simply avoid terrain over 35 degrees in the higher elevations. You might be able to get away with skiing steeper terrain, but it is a roll of the dice given the current conditions.
Another modest batch of precipitation will refresh the riding conditions. It will also require being on the lookout for issues related to storm snow instabilities.
Loose snow avalanches
These will be generally low volume but easy to trigger in terrain over 40 degrees. This problem is one that becomes more serious when traveling above terrain traps such as trees, gullies and cliff bands.
Storm Slabs & Wind Slabs
It will be possible for humans to trigger newly formed slabs in steep terrain today. Winds have been relatively light but enough to create new slabs up to a foot in depth. Sticking to terrain 35 degrees and under, especially on leeward upper elevation slopes will be the best way to avoid this problem today.
Cornices continue to grow and build above many starting zones. Give cornices a wide berth when traveling along ridge crests. Pay attention to the terrain above you as well. If you find your group below cornices spread out and only expose one person at a time.
In the past 24 hours the mountains around Eastern Turnagain Arm have picked up ~5 € of new snow with ~.3 € of snow water equivalent. Ridgetop winds have been out of the East at 12 mph with gusts to 38 mph. Ridgetop temps have averaged in the single digits F and have been gradually climbing overnight into the low teens F.
Today expect snow showers to continue through the morning hours with potential for clearing skies by the afternoon. Snow accumulations of 2-4 € are possible. Winds will be light out of the East at 5-10 mph. Temperatures at 1,000′ will climb into the high teens to low twenties F.
The massive upper level Low pressure system that has been parked over much of the state will continue to bring alternating bands of precip and clear skies until tomorrow. That system will begin to break down beginning late tomorrow. Expect more precip and rising temperatures as we head into the middle part of the week.
|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.