Summit Lake: We saw multiple recent small human-triggered avalanches at Colorado yesterday, including one that we triggered with a ski cut. These were 6-10” deep, about 50’ wide, and ran anywhere from 20-100’ downslope. More details here.
|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|
It is still possible to trigger an avalanche up to 1-2’ deep where a stiff slab of snow is capping a persistent weak layer of buried surface hoar and/or near-surface facets. Persistent problems are tricky since they will sometimes, but not always, give you warning signs when they are present. Whenever this snowpack is giving you clear feedback like shooting cracks (see photo below) or collapsing, it is time to dial down your terrain use and stick to low-angle slopes. In the absence of these clear warning signs, look for other clues like previous wind-loading patterns. Do you see a smooth pillow of snow adjacent to a scoured slope? Are you noticing a hollow, punchy slab at the snow surface? These are indicators of previous wind loading, and today it will still be possible to trigger an avalanche where this kind of slab is present. We know the buried weak layers are present on most slopes in our area. They key to safe travel today is recognizing and avoiding steep slopes where there is a stiff slab of snow on top of these persistent weak layers.
Winds are expected to pick up later in the day, with increasing cloud cover as the upper-level winds shift directions. Pay attention to fresh wind slabs forming with the stronger winds, as they will be sensitive to human triggers, and they have the potential to make larger avalanches where snow is getting loaded on top of pre-existing wind slabs.
Loose Snow Avalanches (Sluffs): The surface snow is dry and loose in areas that have been sheltered from the wind. Be aware of fast-moving and high-volume sluffs in steep terrain, which can have serious consequences if they carry you into terrain traps like cliffs, rocks, trees, or gullies.
Cornices: Large cornices are peeling away from ridgelines, opening up large cracks and becoming especially sensitive. 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 have opened up throughout the area. These avalanches are unpredictable and they are large since 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.
Yesterday: A strong temperature inversion kept temperatures down in the single digits to low teens F at lower elevations, with highs in the mid teens to mid 20’s F at upper elevations. The inversion kept a thick layer of valley fog in place, which reached up to around 1800’, and was thick enough to bring a trace of snow to Girdwood. Skies were clear above the fog. Winds were calm to light, blowing 0-10 mph at ridgetops with variable directions.
Today: A change in weather pattern is on the way today, with increasing cloud cover and easterly winds picking up to 15-20 mph this afternoon. High temperatures are expected to reach the mid- to upper teens F, and no precipitation is expected during the day.
Tomorrow: Easterly winds continue to increase tonight, with sustained speeds around 30 mph and gusts approaching 40 mph by tomorrow morning. Temperatures are expected to dip down into the low teens F tonight, with highs expected in the upper teens to mid- 20’s F tomorrow. We are expecting to see some snow tonight and tomorrow, with 1-5” expected by the end of the day.
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||4||0||0||116|
|Summit Lake (1400′)||-4||0||0||42|
|Alyeska Mid (1700′)||6||0||0||106|
RIDGETOP 24-hour data (6am – 6am)
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||10||NE||2||6|
|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.