Yesterday we saw multiple small to large natural avalanches near the south end of Turnagain Pass (more info here). Most of these were partially filled in by new and blowing snow, but look to have occurred during the tail end or immediately after the Tuesday/Wednesday storm. Most of this activity was on terrain that had been wind-loaded, and they looked like they only involved new snow. The larger ones were big enough to bury a person.
|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|
The northwest winds are going to pick up today before dying down later tonight, and it’s looking like they are going to get strong enough to impact more of Turnagain Pass. Weather stations have been showing sustained speeds around 10-15 mph with gusts of 25-30 mph at Turnagain Pass– including the Sunburst station, which tends to be sheltered from these northwest winds. Our core forecast zone has been relatively protected for the past few days, with speeds around 25-40 mph for most of the day in Summit yesterday, and the AKRR mile 43 station showing gusts as high as 97 mph yesterday morning. We are expecting to see sustained speeds around 20-30 mph in the Turnagain Pass area today. Long story short, it is likely we will be able to find reactive wind slabs today, especially in the mid and upper elevations.
These fresh wind slabs are forming on top of a layer of facets in a lot of terrain, which will make them especially sensitive initially, and will most likely keep them reactive a little longer than your typical wind slab. The best way to stay out of trouble today is by avoiding wind-loaded terrain. The most dangerous slopes will be just below ridgelines, in steep gullies, and on convex rollovers. These northwest winds tend to load terrain differently than our more common easterly winds, so be on the lookout for fresh wind slabs in unusual areas. You should be able to find generally safer conditions (and higher quality snow) in terrain that has been sheltered from the winds.
If these outflow winds end up missing Turnagain Pass again, conditions won’t be quite as dangerous. You should be able to assess winds from a distance by looking for plumes of snow blowing off ridgelines. It is easy to identify wind slabs up close as you travel by stepping off the skin track and feeling for dense, stiff snow on top of softer snow. You can also use small test slopes to see how the new snow is behaving. Just be sure to use slopes that couldn’t produce an avalanche big enough to bury or injure someone.
Checking out a recent avalanche on the north side of Cornbiscuit. This avalanche was fairly small, but there was enough debris piled up in the gully below it to easily bury a person. Photo: Peter Wadsworth. 12.08.2022
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Yesterday: Skies were mostly sunny, with temperatures slowly dropping from the mid 20’s to the mid teens F. There were strong northwest winds around much of the larger area, but Turnagain Pass and Girdwood stayed relatively calm, with sustained speeds of 5-15 mph and gusts of 25-30 mph. Compare this to the Mile 43 weather station, which had sustained speeds of 25-45 mph and gusts as high as 97 mph.
Today: Winds are expected to increase today for our core forecast area, with sustained speeds of 20-30 mph and gusts of 30-50 mph. Winds should be strongest later this morning, but are expected to continue through the day before calming down later tonight. Temperatures will continue their slow decline today, with highs in the single digits to low teens F, dropping to the single digits above and below 0 F tonight. Skies will be mostly sunny and no precipitation is expected.
Tomorrow: Things begin to change once again tomorrow. Cloud cover will increase as winds shift back to the southeast at 5-10 mph. High temperatures will be in the single digits to mid teens F, and no precipitation is expected during the day. It is looking like a proper storm is on the way for Sunday and Monday.
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||17||0||0||30|
|Summit Lake (1400′)||18||0||0||21|
|Alyeska Mid (1700′)||17||0||0||29|
|Bear Valley (132′)||25||0||0||–|
RIDGETOP 24-hour data (6am – 6am)
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||14||NW||10||25|
|05/22/23||Turnagain||Avalanche: Tincan||Nick D'Alessio|
|05/12/23||Turnagain||Avalanche: Tincan, Sunburst, Magnum, Cornbiscuit||Heather Thamm|
|05/07/23||Turnagain||Observation: Tincan – Bear Tracks||CNFAIC Staff|
|05/05/23||Turnagain||Observation: Seattle Ridge||AS/ WW Forecaster|
|05/02/23||Turnagain||Observation: Cornbiscuit||Schauer/ Sturgess Forecaster|
|05/02/23||Turnagain||Observation: Seward Hwy Turnagain Pass||Joel Curtis|
|04/30/23||Turnagain||Observation: Magnum||Ayla, Kit Crosby, Barton|
|04/29/23||Turnagain||Observation: Tincan||John Sykes|
|04/28/23||Turnagain||Avalanche: Taylor Pass/Pastoral||Schauer/ Creighton Forecaster|
|04/28/23||Turnagain||Avalanche: Tincan||Andy Moderow|
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.