|Signal Word||Size (D scale)||Simple Descriptor|
|Small||1||Unlikely to bury a person|
|Large||2||Can bury a person|
|Very Large||3||Can destroy a house|
|Historic||4 & 5||Can destroy part or all of a village|
With benign weather today, as we trend towards overall LOW danger in the Turnagain pass area, only very specific terrain still warrants extra caution at this point. Steep (above 35°), rocky, unsupported slopes with variable snowpack coverage remain suspect for triggering a deep persistent slab avalanche. If hitting a thin spot does initiate an avalanche it could be deep, running on weak faceted snow at the ground. We are in the phase where there is a low probability of this but due to the depth, the consequences remain high. There are many pieces of data that are in our favor. It has been two weeks since the last human triggered avalanche on this layer and neither the last storm snow load or the last wind loading event were known to have triggered avalanches to the ground. Many skiers and snowmachiners have tested steeper slopes over the past two weeks. This all points to the snowpack adjusting and stabilizing. However, we still do have the poor snowpack structure above 2500′. We know the weak snow is there under a very hard slab of snow and if this happens to fail it could be dangerous. It’s this remaining, ‘What if?’ that sucks. The most likely places to trigger a large avalanche failing near the ground, will be in the areas with the thinnest snowpack in steep and rocky terrain. The total snow depth gets thinner as you head south in Turnagain Pass and to the north around Crow Pass. In the upper elevation terrain in Placer Valley and Skookum we have no data on the snowpack and have to assume guilty until proven innocent.
As Andrew said in the forecast yesterday, ‘At some point– hopefully sometime soon– we will be able to tuck this problem away as an additional concern. For now, we are still finding weak snow at the ground, and we are actually getting some stability tests to fail in this layer, making this our primary concern for today.’
Besides this lingering deep slab issue, normal caution is warranted in avalanche terrain today. Steer clear of cornices, watch for lingering wind slab pockets just off of ridgelines and for sluffing in steep terrain, and pay attention to changing conditions if winds ramp up more than forecasted today.
Yesterday: Skies were mostly cloudy, unless you happened to be above the low stratus layer. There were light snow showers near the end of Turnagain Arm in the morning. Winds were calm and temperatures were in the low 30°Fs at sea level and mid to high teens in the Alpine. Overnight skies were partly cloudy, winds were calm and temperatures were in the high teens to low 20°Fs.
Today: Skies are forecast to be mostly cloudy with a chance of snow showers. Easterly winds bumped up a bit early this morning at ridgetops, blowing 10-15 mph with gusts into the 20s. These should ease by mid afternoon. Temperatures will be in the 20°Fs. Overnight skies will be mostly cloudy with a continued chance of snow showers. Winds will be light and northeasterly and temperatures will be in the teens to mid 20°Fs.
Tomorrow: Cloudy skies and a chance of snow with light northerly winds and temperatures in the 20°Fs. Looking ahead there is some uncertainty about the next storm developing for the weekend and how it will impact this region. Stay tuned! Think cold thoughts.
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||22||0||0||59|
|Summit Lake (1400′)||20||0||0||25|
|Alyeska Mid (1700′)||23||0||0||59|
RIDGETOP 24-hour data (6am – 6am)
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||18||E||2||12|
|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: 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.