We continue to document loose and very weak facets between the January melt/freeze crust and the February 7th storm snow. This layer was responsible for a number of small human triggered avalanches in the last week. It continues to be the most likely culprit for significant avalanche activity today, especially when combined with new snow and wind. Check out this observation for photos and snowpit data regarding the facet layer.
Avalanches witnessed on this layer have thus far maintained a consistent pattern with relatively small size (12-20″ deep), and lower volume. Keep in mind that bigger and steeper terrain will produce larger and more dangerous avalanches. With more snow and wind the depth of this slab layer will be reaching 24-30″ in wind loaded areas.
The 2 properties necessary to create this type of avalanche that are not always found –
2. A faceted interface between the new snow (Feb 7th storm) and the underlying crust (January melt/freeze). In places where the facets are present, this is a significant weak layer consisting of loose sugary grains with poor bonding.
Yesterday afternoon we witnessed a very small natural avalanche occur during a short spell of wind. Our light dry snow on the ground is easily transported by wind and wind slab can build quickly with only moderate wind velocities. Additional storm snow by itself is probably not enough to be a significant avalanche problem, but combined with wind it will produce pockets of unstable snow.
Wind slab is expected to be isolated to higher elevations above treeline, and may not form if the wind stays light today.
Just a couple inches of snow had fallen yesterday before we got a clear break and periodic wind activity. Wind was reaching gusts to 52 mph and blowing snow around at ridgetop levels.
The large low pressure system over Kodiak is sending our region waves of cold precipitation today. As of this morning we have another 3-5 inches of snow on the ground and it is forecasted to continue through the end of Friday. Wind has backed off a little. Temperatures remain cold but are increasing slightly. Currently Center Ridge snotel is reading 11.5 degrees.
Unsettled storm patterns will continue through the weekend, originating from the low pressure system in the northwest gulf. We can expect more of the same weather for a few more days.
|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.