Summit Lake: Skiers reported a natural avalanche failing near the surface on a wind-loaded slope in the Colorado/Fresno area.
|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|
Last week’s snowfall buried a layer of surface hoar and near-surface facets that has been producing avalanches on wind-loaded slopes for the past few days. We are expecting the winds to calm down today, but unfortunately the avalanche danger will not do the same. The nature of these persistent weak layers is that they are capable of producing avalanches long after any kind of loading event. For today, the best way to stay out of trouble will be by identifying and avoiding any steep slopes with stiff snow at the surface. After several days of cold and clear weather, most slopes have 6-8” loose, unconsolidated snow at the surface unless they have seen any wind-loading since Friday. These slopes with loose snow at the surface are not capable of producing persistent slab avalanches because they are lacking a cohesive slab capable of propagating a fracture. The danger will lie on the slopes that have seen wind loading since Friday, which has built a dangerous structure with a relatively stiff slab of snow at the surface sitting on top of a layer of relatively weak snow buried 1-2′ deep.
Because we are dealing with a persistent weak layer, slopes that have seen wind loading will not gain strength as quickly as they normally would. In addition to monitoring surface conditions, be on the lookout for other key indicators of instability- shooting cracks, collapsing, and fresh avalanche activity.
Loose Snow Avalanches (Sluffs): Several days of cold and clear weather has kept the surface snow dry and loose in areas that have been sheltered from the wind. Be aware of fast-moving and high-volume sluffs in steep terrain, especially if you are traveling near terrain traps like cliffs, rocks, trees, or gullies.
Cornices: Large cornices are starting to peel away from ridgelines, opening up large cracks and becoming especially sensitive to human triggers. If you are traveling along ridgelines be sure to give them plenty of space, and minimize the amount of time you spend traveling below them.
Glide cracks continue to open up throughout the area. These avalanches are unpredictable and large– they involve the entire season’s snowpack. Avoid spending any time on or below slopes with glide cracks, as they can release unexpectedly. If you see any new glide activity, please let us know here.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880')||2||0||0||123|
|Summit Lake (1400')||-6||0||0||42|
|Alyeska Mid (1700')||2||0||0||109|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400')||2||VAR||5||16|
|05/18/21||Turnagain||Observation: Tincan Ridge||Joe Kurtak|
|04/30/21||Turnagain||Observation: Sunburst||W Wagner Forecaster|
|04/27/21||Turnagain||Observation: Tincan Ridge||Joe Kurtak|
|04/26/21||Turnagain||Observation: Magnum||Creighton/ Hoople|
|04/25/21||Turnagain||Observation: Sunburst||Nick D'Alessio|
|04/24/21||Turnagain||Observation: Airplane obs||Johnston-Bloom / DiJulia /Hilliard Forecaster|
|04/24/21||Turnagain||Observation: Corn biscuit||Heather Johnson|
|04/23/21||Turnagain||Avalanche: Lynx Ck Drainage||W Wagner Forecaster|
|04/23/21||Turnagain||Avalanche: Sunburst||Eeva Latosuo|
|04/23/21||Turnagain||Observation: Center Ridge Turnagain pass||Joe Kurtak|
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.