New storm snow proves to be a valid concern today after several observations this week of human triggered avalanches and some downright spooky test results from our snow pits yesterday, all from below tree line. As we have watched our seasonal snowpack more than double in a few short days, the weak layers we’ve been talking about for the last month finally have a 2-5 foot slab sitting on top of them. This is the piece of the avalanche puzzle that has been missing until this week! The new slab sits on several different weak layers, any of which may fail with the weight of a person causing an avalanche that will prove unmanageable in steep terrain. We are in a direct-action avalanche situation and triggering an avalanche should be of no surprise today based on what we know about our weak foundation and overlying storm slab. The old mantra to stay out of the mountains for at least 24 hours during and after a storm rings loud and true this week!
Easterly winds looked to have picked up overnight with the approach of this latest low-pressure system. Even though we have limited data from upper elevations (due to poor visibility and dangerous avalanche conditions) we can safely say that tender wind slabs are forming and most likely avalanching naturally in our core advisory area. Human triggered avalanches will be very likely in terrain above tree line today. AKRR and DOT crews were able to affect wind slabs with artillery above Turnagain arm yesterday. Shots were yielding consistent results producing avalanches big enough to destroy a small building or break trees. We can expect wind slabs to continue to build today in our upper elevations. If these don’t avalanche naturally, only time will help to heal these slabs.
Well the snow continues to pile up this week as the pattern change we were all hoping for did not disappoint! Turnagain pass saw an additional 8-10 € of snow yesterday, turning to a rain-snow mix at 1000′ overnight. Winds looked to have peaked from the east in the low 80’s last night.
Today looks to be more of the same with another 3-6 € of snow expected and moderate winds from the east. The rain/ snow line will be hovering somewhere between sea level and 1000 feet as this latest low begins to dissipate today.
Looking out toward the weekend there appears to be more unsettled weather in our future!
Total snow accumulation beginning early morning on the 24th:
Girdwood Valley €“ ~50 € snow with 5 € of water equivalent
Turnagain Pass €“ ~45 € snow with 4.3 € of water equivalent
Summit lake €“ ~12 € snow with 1.1 € water equivalent
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).
Fitz will issue the next advisory Friday morning December 28th.
|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.