There was a skier triggered slab avalanche in the Library yesterday. The skier was able to arrest on the bed surface and was not carried. The slab was about a foot deep and released on the layer of buried surface hoar we have been talking about. This was second line of the day for the party involved and last skier in the group. The group noted the first line skied had no obvious signs of instability. Thanks to the party involved for sharing information and 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|
Many people were out enjoying the sunshine and soft snow over the weekend. Today will be another beautiful, chilly day to be out. However, avalanche conditions are a bit tricky right now and there are a few things to take into consideration. First and foremost, triggering a slab avalanche is possible. Second, pay attention to wind-loading. There is plenty of soft snow available for transport. Winds are blowing from the northwest, these get channeled through the southern end of Turnagain Pass from the south and were strong enough to move snow yesterday. Today will be the second day of this wind pattern. Prior to yesterday winds were from the east. Slopes that have seen even just a touch of wind over the past few days may have developed a slab over the weak snow that is unfortunately lurking below. Which brings me to the third thing to remember when choosing terrain today; there is a weak layer of surface hoar and near surface facets underneath the most recent storm snow. People have been triggering avalanches that have been releasing on this layer for the past three days in terrain with a little bit of wind effect. The question of today will be whether or not a slab has formed on the slopes you want to ride. If you are headed out today watch for:
For people getting into big terrain, soft wind slabs may be found not only along ridgelines but lower on the slope. Even a small slab triggered could entrain a large amount of snow if the slope is steep and sustained and take you for a bad ride.
Loose snow avalanches (sluffs): Sluffs are likely to be high volume and fast running. They could entrain not only all the new snow, but a portion of the facets that sit below it and could have serious consequences if they carry you into terrain traps like cliffs, trees, or rocks.
Cornices: We have recently seen large cornices peeling away from ridgelines, opening up large cracks (there are some good photos here). Be sure to give them plenty of space, and minimize the amount of time you spend below them.
Glide cracks exist across the forecast area. Remember it is important to limit time spent underneath them. Glide avalanches are totally unpredictable, not triggered by people and are the entire snowpack sliding at the ground. This type of avalanche could be large and unsurvivable if you happened to be in wrong place when one releases. If you see recent glide activity please let us know.
Yesterday: Skies were mostly clear with some valley fog along Turnagain Arm and into Girdwood. Temperatures were in the single digits to low teens. Winds were northwesterly 5-15 mph gusting into the 20s. Overnight skies were mostly clear, temperatures dropped to the low single digits or below 0°F in some locations, winds remained northwesterly 5-15 mph gusting into the 20s.
Today: Another day of clear skies and northwest winds 5-15 mph with gust into the 20s. Temperatures will be in the low single digits to below 0°F. Skies remain clear overnight and temperatures will slowly rise. NW winds continue until early Tuesday morning when they shift to the east.
Tomorrow: Skies will be sunny in the morning with increasing clouds in the afternoon. Temperatures will be in the mid teens and winds will be light and easterly.
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||7||0||0||124|
|Summit Lake (1400′)||-5||0||0||42|
|Alyeska Mid (1700′)||7||0||0||106|
RIDGETOP 24-hour data (6am – 6am)
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||6||NW||3||10|
|02/25/21||Turnagain||Observation: Seattle flats, above power line||Carly AAS Level 1|
|02/25/21||Turnagain||Avalanche: Cornbiscuit North face||CNFAIC Staff Forecaster|
|02/25/21||Turnagain||Avalanche: Tincan Proper||CNFAIC Staff Forecaster|
|02/25/21||Turnagain||Avalanche: Johnson Pass area||W Wagner Forecaster|
|02/24/21||Turnagain||Observation: Eddies||Johnston-Bloom / Roberts Forecaster|
|02/23/21||Turnagain||Observation: Silvertip||Nancy Pfeiffer|
|02/22/21||Turnagain||Observation: Magnum||Schauer/ Latosuo Forecaster|
|02/21/21||Turnagain||Avalanche: 3400′ SW Eddies ridge||Peter Ostroski|
|02/20/21||Turnagain||Observation: Shark’s Fin||Schauer/ Jonas Forecaster|
|02/17/21||Turnagain||Observation: Sunburst||Johnston-Bloom / Roberts 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.