Loose Snow Avalanches
New snow in the past 24 hours fell in many places without any associated winds. Up to a foot of new snow can be found in the upper elevations with half that amount in the lower elevations. This snow is “right side up”, as temperatures overnight have gradually cooled. Loose snow avalanches will be a concern on steep upper elevation slopes today. Periods of sunshine will increase the likelihood of triggering these slides. These avalanches have the potential to knock people off of their feet or snowmachines. As such it will be best to avoid steep slopes above terrain traps where sloughing could pull people into gullies, over cliff bands and into trees.
In the upper elevations isolated pockets of older wind slab may be triggered by a skier or rider today. These pockets will be harder to detect, as a blanket of lighter density new snow sits on top of these slabs. Staying off of steep previously wind loaded terrain features will help in avoiding this problem today.
With light to moderate winds forecasted for today, expect to see shallow new wind slabs forming near ridgetops through the day. With ample light density snow available for transport, expect these slabs to form easily and be most sensitive as they are forming.
The mid elevations (between 1,500-2,800′) have a snowpack structure that has some potential to produce larger more dangerous avalanches. A crust formed in late January has a very thin layer of weak snow above it in many areas. Above that weak layer are slabs ranging in depth from 1-3 feet. We have been investigating the likelihood of triggering an avalanche on this interface and have found mixed results within our forecast zone. In some areas snowpit tests have shown this layer to be reactive and in other areas it has been a non issue. While we’ve only had one report of a human triggered avalanche on this layer in the last week, the potential still exists. The best way to avoid this problem is by managing your terrain and staying away from potential trigger points (e.g., steep rollovers, areas of thin snow) within this elevation band.
Snowfall that began in the early morning hours on Sunday have accumulated up to a foot of new snow in the higher elevations. Water amounts across the area range from .75″ in the Girdwood Valley, .5″ on Turnagain Pass and .3″ at Summit Lake. Winds have been very calm out of the North. Temperatures have been on a steady decline this morning with ridgetop stations reporting an average of 10 degrees F.
Today we should expect to see snow showers tapering off in the morning giving way to clear skies by this afternoon as a brief pause between storms takes hold. This break will be short lived, as the next low pressure system moves into the area from the Southwest by tomorrow afternoon.
Wendy will issue the next advisory tomorrow morning, February 19th.
|04/09/21||Turnagain||Observation: Girdwood to Turnagain Road Observations||W Wagner Forecaster|
|04/05/21||Turnagain||Avalanche: Resort bowl Seattle creek head wall||Clint Kyffin|
|04/04/21||Turnagain||Observation: Center Ridge||Andy Moderow|
|04/03/21||Turnagain||Observation: Repeat Offender – Seattle Ridge||Troy Tempel|
|04/02/21||Turnagain||Observation: Seattle Ridge||Wagner / Schauer Forecaster|
|04/01/21||Turnagain||Observation: Pete’s||Schauer/ Cullen Forecaster|
|03/31/21||Turnagain||Observation: Tincan||Schauer/ Rothman Forecaster|
|03/30/21||Turnagain||Observation: Eddies||Johnston-Bloom / Kinney Forecaster|
|03/30/21||Turnagain||Observation: Sunburst North||lance breeding|
|03/28/21||Turnagain||Observation: Sunburst||Aleph Johnston-Bloom 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.