It was a quiet day in the backcountry yesterday with no slab avalanche activity reported. Though we are starting to see some sluffing in the loose facets in very steep rocky terrain. The snow surface conditions in most areas consist of loose recycled powder with 1-3cm surface hoar on top.
As far as our snowpack situation and the “persistent slab” problem goes, it continues to be a concern. Though the slab is slowly deteriorating into one large weak layer with cold, clear and calm weather there are still places at the upper elevations that have the potential to avalanche. We found one such area yesterday in the Turnagain Pass region where pit results pointed to instability on a suspect slope containing the slab/weak layer combo. What we are finding is that there are slabs that still have the potential to propagate but triggering them is becoming more difficult. A video and more details of our field day HERE.
Slopes that are most suspect to avalanche are those in the 40 degree range and unsupported from below. These slopes are also not the most enticing due to thin coverage. Using a pole to feel the snowpack structure and watching for collapsing (whoomphing) and cracking will be your best clues to suss out this poor structure.
Other observations that have come in from surrounding areas show current instability as well as future weak layers when we get our next bout of snow. One from the Girdwood Valley and one from the Lost Lake area near Seward.
Below treeline we continue to see a snowpack that is rotting away with the cold and consists of faceted snow with a degrading crust ~10” deep. Where slopes are steep enough, initiating sluffs in the loose facets is possible.
The image below is an avalanche incident rose from Nov 2nd (first snowfall on the October facets) to present, Nov, 24th. The rose shows aspect and elevation of all avalanches (both natural and human triggered) we have recorded. We feel all of these slides broke in the October snow. The last avalanche reported was the Sunburst natural on Nov 21st / 22nd.
Single digit temperatures are locked in at the lower elevations and parking lots and look to remain this way for several more days. At just 2000′ however, temps are up to 20F and in the high teens on the peaks. This is quite the inversion. The easterly winds that have remained very light did bump up slightly last night (~15mph) on the ridgetops. The winds are back down to ~5mph this morning where they are likely to stay. No precip is forecast for several days…
Though there are a few small low pressure systems in the Gulf, they are not impacting our region – what we need is a large scale pattern shift and the removal of the blocking high pressure over mainland Alaska. Hopefully we will see this later this coming week.
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).
I will issue the next advisory Tuesday morning, November 27th.
|04/21/21||Turnagain||Observation: Sunburst||Schauer/ Behney Forecaster|
|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|
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: email@example.com
|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.