Turnagain Pass: We saw a bunch of fresh wind slabs releasing naturally yesterday as the strong outflow winds gained enough strength to start reaching into the lower elevations in the Turnagain Pass area. Most of the activity we observed was along the South and East aspects of Seattle Ridge, but that is also where there was good light for viewing avalanches so there were likely many more hiding in the shadows. Here are a few examples, see this observation for more photos.
|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|
After several days of outflow winds, they finally built up enough wind speed to reach into the treeline elevations of Turnagain Pass yesterday. We observed several natural avalanches along Seattle ridge and saw active transport along all the ridgelines in the area. Surface conditions range from soft snow in protected areas to areas where the wind has blown off all the fresh snow down to a melt freeze crust.
The main concern for today will be lingering wind slabs 1-2′ deep from yesterdays wind event. These are most likely to be found on the leeward side of ridgelines and wind loaded gully features. The distribution of wind slabs in Turnagain Pass is more widespread than the past several outflow wind events because the winds affected lower elevation terrain yesterday.
To identify features that are potentially holding onto lingering wind slabs it is important to step out of the skin track and feel the surface snow conditions around you. Look for stiff and hollow feeling snow on the surface and areas where the winds have transported the snow into large drifts or pillows. Using small test slopes can be a good way to see how reactive wind slabs are before committing to more consequential terrain. These wind slabs were deposited on top of a layer of surface facets which could make them release on lower angle slopes and remain reactive for longer than normal.
Yesterday: Clear, cold, and windy. Winds were averaging around 10 mph out of the NW in Turnagain Pass with gusts to 20-30 mph. Much stronger winds were transporting snow along upper elevation ridgelines and in areas exposed to gap winds.
Today: We are transitioning from cold and clear with outflow winds to the onset of our next storm. Winds will switch to the South and decrease to 5-10 mph this morning. Temperatures will remain in the single digits to low teens. Cloud cover is expected to move into the area today, starting at higher elevations and gradually descending. Snowfall associated with our next system should start either late tonight or early Sunday morning.
Tomorrow: Heavy snowfall is expected on Sunday. Depending on the timing of the storm we could see anywhere from 6-12″ during the day on Sunday. From Sunday morning through Monday afternoon we are expecting 2-4′ of new snow, with higher totals in coastal areas. Temperatures will increase to the teens to low twenties on Sunday, and snowline is expected to remain at sea level. Winds are also expected to increase with the storm, with averages in the 30-40 mph range and gusts of 60+ mph.
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||15||0||0||30|
|Summit Lake (1400′)||14||0||0||20|
|Alyeska Mid (1700′)||14||0||0||28|
|Bear Valley – Portage (132′)||21||0||0||–|
RIDGETOP 24-hour data (6am – 6am)
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||13||NW||9||30|
|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.