An increase in ridgetop wind today, into the 20-30mph range from the east, will be enough to form shallow fresh wind slabs on the lee sides of ridges and gullies. With plenty of loose existing snow, warmer temperatures and the possibility of an inch of new snow, drifts should be fairly cohesive. These will be sitting on loose, non-cohesive snow that will make them touchy. Keep an eye out today for areas where the wind is picking up and loading slopes. Stiffer supportable snow, with any cracking and collapsing, will be bulls eye clues you found a wind slab and if the slope is steep enough, could slide.
The persistent slab problem has not entirely gone away as weak snow still lurks near the ground. See observations from yesterday. With added weight of a wind slab and a person there is the possibility of a slide breaking to the ground. In this case, the consequences are higher than with triggering a fresh wind slab. Expect any slide triggered, no matter how small, to run far.
Sluffing in the weak faceted (sugar) snow is becoming quite prevalent. This video from yesterday shows just how easy it is to initiate one of these sluffs. Even though these are easy to trigger they are also easy to avoid due to their predictable nature. Know where your sluff will go (as to not be overrun from behind) and also watch that you do not hit someone below as they are running to valley bottoms.
This is a good example of how weak our snowpack is right now. The snow has lost so much cohesion that if nudged down a slope it will gain momentum, entrain more snow and run till the slope angle lessens. Once a fresh layer of snow falls on this existing surface (Saturday through Sunday) the sugar snow wil have a hard time holding any new snow to the ground and avalanche conditions will rise rapidly.
Clear skies yesterday were replaced with cloud cover overnight and increased the frigid temperatures at Portage (10ft above sea level) from -22 to +2F overnight. Temperatures at the mid elevations and on the ridgetops have increased as well are in the 15-20F range. Winds are still light blowing 5-10mph from the NE and gusting 10-15mph. Expect temperatures to rise another degree or two throughout the day and winds to increase into the teens gusting in the 20’s from the east. We are likely to see some flurries and possibly an inch of snow today.
The big news will come Saturday and Sunday when a change in the weather pattern really sets in. Models are suggesting around 4-7 € of snow on Saturday in the Eastern Turnagain Arm area (.5 water equivalent) and 12-22 € of snow for Saturday night and Sunday (between 1 €“ 2 € water equivalent). Stay tuned as we get closer to the weekend.
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).
Graham will issue the next advisory Friday morning, December 7th.
|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.