As of Saturday, March 28th a stout crust was covering the snowpack at almost all aspects and elevations. This crust is still in place and has locked up the snowpack and put a stop to most avalanche issues. Until it gets warm enough to melt the surface crusts, triggering an avalanche will remain unlikely. Hence, that will be the big question moving forward. However, there is one wild card and that is the glide avalanche…
The afternoon sun lights up surface crusts in 1st Bowl (Main Bowl) on the backside of Seattle
Ridge on March 26th.
A 1″ melt-freeze surface crust exists at 2,600′ on a north aspect on Seattle Ridge. It only took one warm cloudy day (March 25th) to heat the northerly slopes up enough to melt the surface, which is now why there is a crust on north aspects.
Glide avalanches: Whether a frozen surface or not, glide avalanches could still pose a problem. This type of avalanche is not associated with human triggers and is completely unpredictable as to if or when it will release. What one can do is watch for glide cracks in the snowpack and limit any exposure under them. There are a few glide cracks beginning to open and several released during the warm day on March 26th. Don’t mess with the brown frown!
Avalanche Outlook for this week:
Sunny skies with cool temperatures look to remain until Wednesday, April 1st. Solar warming on southerly slopes, combined with light winds, may be enough to soften and melt surface crusts. If the crusts melt and the cohesion is lost, the avalanche danger will rise. Both wet loose and wet slab avalanches will become possible. Watching for this will be the key to avoiding avalanche issues during the beginning of the week. Later in the week with a chance of rain and snow, paying attention to temperatures and precipitation amounts will be important for assessing avalanche danger. Rain on snow can cause wet avalanches. Where it is cold enough for snow, storm slabs may develop if the new snow adds up to 6″ or more and does not bond well to the existing snow surface. Here is quick rundown on the different avalanche problems:
Wet loose avalanches: Watch for daytime warming to soften surface crusts on steep southerly slopes. Later in the week, watch for warm cloudy/rainy weather to soften the crusts in the lower elevations. Once the crusts become punchy, wet and saturated, wet sluffs will be easy to trigger. These can run much further than expected on large slopes and entrain a significant amount of snow.
Wet slab avalanches: Similar to wet loose avalanches, once the surface crusts melt, wet slab avalanches will become possible. These could also have a dry slab character in the higher terrain where dry snow exists under the surface crust. Areas most suspect are those with a shallow snowpack harboring weak faceted snow in the mid and base of the pack, such as on the south end of Turnagain Pass and in the Summit Lake area.
Cornice falls: Warming during the heat of the day can weaken cornices and make them more tender to trigger. Something to keep in mind for the remainder of the snow season.
New snow avalanches: If more than a few inches of snow falls later this week, avalanches related to the new snow will be possible. These could include storm slabs, wind slabs and sluffs. Paying attention to how much new snow falls, if the wind is blowing it into slabs and how well it is bonding to the curst underneath will be key.
For the most up to date weather please see our weather page.
Snowpack temperature: Have you seen the BeadedStream temperature array lately? You can watch the snowpack slowly warm during the springtime. The data takes some digesting, but take a minute to see what’s there. The instrumentation sits at 2,300′ on Tincan and is a 3m (9′) cable with temperatures sensors every 15cm (6″). The cable starts in the ground for ground temperature then extends through the snowpack into the air. Check it out.
|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.