The storm on Monday dropped 12-15 inches of snow in some parts of Anchorage. You can expect to find similar amounts in the Turnagain forecast region, with Girdwood getting a little more in the areas we’ve surveyed. A notable feature of this storm was the cold temperatures. The snow fell cold and dry, making for a light density powder with low water content. Despite only moderate wind during the storm, the light powder was easily moved around by wind. There are a lot of wind affected slopes, varying from scoured surfaces on one aspect, to stiff wind slab, to sheltered pockets of loose powder.
Today, the wind slab is my greatest concern. Yesterday we found a couple pockets of stiff supportable wind slab that collapsed with a “whoomph” when we skied across (see pit profile and description here). Given a steep enough slope, this would probably initiate a small avalanche. Furthermore, the problem can be even worse if it sits on top of a sun crust. The two things I would actively try to avoid today – stiff wind slab on steep slopes, and southerly aspects where reactive sun crusts may be found.
If you can avoid these two issues, there are still pockets of good quality loose powder to be found.
The recent stretch of sunny weather produced 2 specific weak layer concerns.
1. Sun crusts on south aspects. We found at least 3 distinct buried sun crusts yesterday, with the top one being moderately weak with a tendency to propagate. A number of smaller skier triggered avalanches have been reported in the last week, and the majority seem to be on southerly slopes, probably because of the sun crust layers.
2. Non sun affected slopes simply got weaker in the surface snow during the 2 weeks of clear weather. Weak snow by itself isn’t necessarily a problem, until you get stronger or stiffer snow on top of the weak snow.
Following the snow storm two days ago, the weather turned cold and sunny. Last night it got even colder, with temperatures dipping into the negatives. There is a mild temperature inversion, making the mountains slightly warmer than the valleys.
Temperatures at 6am
Portage valley -15 degrees
Turnagain Pass Center ridge 2.7 degrees
Summit Lake -7.3 degrees
Alyeska, top chair 6 is 4 degrees
We had no measureable precipitation yesterday and wind was light from the north at most of the weather stations.
Today’s weather looks fairly tame if you can deal with the cold. Incoming in the next few days is a larger storm system with warmer temperatures and more precipitation.
Graham will issue the next advisory tomorrow morning, March 28th.
|01/16/21||Turnagain||Avalanche: Tincan Trees||A Schauer Forecaster|
|01/15/21||Turnagain||Observation: Sunburst||Schauer/ Wunnicke Forecaster|
|01/13/21||Turnagain||Observation: Tincan||Johnston-Bloom / Moderow Forecaster|
|01/13/21||Turnagain||Observation: Center Ridge Meadows||Alaska Avalanche School Rec Level 1 Roberts|
|01/12/21||Turnagain||Avalanche: Seattle Ridge/Center Ridge||A Schauer Forecaster|
|01/11/21||Turnagain||Observation: Tincan Trees||Schauer/ Roberts Forecaster|
|01/10/21||Turnagain||Observation: Center Ridge Meadows||Alaska Avalanche School Pro 1 Course Latosuo|
|01/10/21||Turnagain||Avalanche: Tincan trees||Anonymous|
|01/09/21||Turnagain||Observation: Johnson Pass||Anonymous|
|01/08/21||Turnagain||Observation: Sunburst meadow between Hemlocks||Anonymous|
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.