We have relatively little information from the last 5 days because so few people are getting into the backcountry right now. Conditions are challenging with a hard “chattering” crust below treeline that is a prerequisite before you gain the slightly softer zone above treeline.
The last major high elevation deep slab that we know of was a week ago on Goat Mountain in the Girdwood valley. Remember that this problem doesn’t stabilize quickly like a storm slab problem.
Above treeline the snowpack is thick, with weak snow at and near the ground. We have been able to cause failures on these layers in test pits.
Managing this low likelihood, high consquence problem can be accomplished by limiting travel in steep terrain. If that isn’t an option, then exposing one person at a time to steep terrain will reduce risk exposure.
Recent wind has been limited, so wind slabs are generally older. Above treeline there can be found some soft snow and some wind stiffened snow. Watch out for pockets of stiff wind slab that may fail in small avalanches. Unstable cornices are another subcategory that fits into wind slab concerns.
Wendy posted this summary yesterday, which gives us a good look at the recent weather.
With many days of unseasonably warm weather during January, some of us are wondering just where did we stack up in the monthly averages. There is more data to crunch so stay tuned – but we do have a few sets of interesting numbers. Below are graphs of precipitation, SWE (Snow Water Equivalent) and Temperature.
We have not had any significant precipitation for the past week.
Current weather has a temperature inversion across the region. Sea level temperatures are in the mid to high teens, ridge top temperatures are in the high 20s. Valley fog has dominated Turnagain Arm for a few days, and this will likely continue today. Wind has been light for several days now. These conditions are building surface hoar crystals, which could become a buried weak layer the next time it snows.
The blocking high pressure pattern is expected to continue this week. By the end of the week – computer models are showing a pattern change but the exact nature of that weather remains uncertain.
|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.