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Issued
Sun, January 14th, 2024 - 7:00AM
Expires
Mon, January 15th, 2024 - 7:00AM
Forecaster
Andrew Schauer
Avalanche risk The Bottom Line

Today’s danger is MODERATE above 1000′, and glide avalanches remain our main concern. These strange avalanches are very large and unpredictable, and they have continued to occur in high-traffic areas for over two weeks now. Avoid traveling under open glide cracks whenever possible, and consider alternate routes when common skin tracks or uptracks cross under an active glide crack. It will also be important to look for and avoid steep slopes with a fresh round of sensitive wind slabs up to 1′ deep on the surface, which formed overnight and may remain reactive during the day.

The danger is LOW below 1000′. It is unlikely you will trigger an avalanche below treeline but there is a small chance that a large glide avalanche failing at upper elevations may run into low-elevation runout zones.

 

Special Announcements

Girdwood Forecaster Chat – Friday, Jan 19th! Mark your calendars for Andrew Schauer’s discussion on the different shades of MODERATE danger at the Girdwood Brewing Co. (6:30pm Jan 19). More details HERE.

Sun, January 14th, 2024
Alpine
Above 2,500'
2 - Moderate
Avalanche risk
Treeline
1,000'-2,500'
2 - Moderate
Avalanche risk
Below Treeline
Below 1,000'
1 - Low
Avalanche risk
Mon, January 15th, 2024
Alpine
Above 2,500'
2 - Moderate
Avalanche risk
Treeline
1,000'-2,500'
2 - Moderate
Avalanche risk
Below Treeline
Below 1,000'
1 - Low
Avalanche risk
Mon, January 15th, 2024
Alpine
Above 2,500'
2 - Moderate
Avalanche risk
Treeline
1,000'-2,500'
2 - Moderate
Avalanche risk
Below Treeline
Below 1,000'
1 - Low
Avalanche risk
0 - No Rating
1 - Low
2 - Moderate
3 - Considerable
4 - High
5 - Extreme
Avalanche risk Avalanche risk Avalanche risk Avalanche risk Avalanche risk
Travel Advice Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential. Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain.
Likelihood of Avalanches Natural and human-triggered avalanches unlikely. Natural avalanches unlikely; human-triggered avalanches possible. Natural avalanches possible; human-triggered avalanches likely. Natural avalanches likely; human-triggered avalanches very likely. Natural and human-triggered avalanches certain.
Avalanche Size and Distribution Small avalanches in isolated areas or extreme terrain. Small avalanches in specific areas; or large avalanches in isolated areas. Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. Large avalanches in many areas; or very large avalanches in specific areas. Very large avalanches in many areas.
Recent Avalanches

The glide activity continued yesterday, with a fresh release on the south side of Eddie’s ridge caught on the DOT webcam at Turnagain Pass sometime Friday night or early Saturday morning.

Yesterday’s glide avalanche on the south side of Eddie’s was the latest in a flurry of glide activity in busy areas. Photo from the Turnagain Pass RWIS webcam, 01.13.2024

Avalanche Problem 1
  • Glide Avalanches
    Glide Avalanches
  • Aspect/Elevation
  • Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic (D4-5)
    Very Large (D3)
    Large (D2)
    Small (D1)
    Size
Glide Avalanches
Glide Avalanches are the release of the entire snow cover as a result of gliding over the ground. Glide avalanches can be composed of wet, moist, or almost entirely dry snow. They typically occur in very specific paths, where the slope is steep enough and the ground surface is relatively smooth. They are often proceeded by full depth cracks (glide cracks), though the time between the appearance of a crack and an avalanche can vary between seconds and months. Glide avalanches are unlikely to be triggered by a person, are nearly impossible to forecast, and thus pose a hazard that is extremely difficult to manage.

Aspect/Elevation of the Avalanche Problem
Specialists develop a graphic representation of the potential distribution of a particular avalanche problem across the topography. This aspect/elevation rose is used to indicate where the particular avalanche problem is thought to exist on all elevation aspects. Areas where the avalanche problem is thought to exist are colored grey, and it is less likely to be encountered in areas colored white.

Likelihood of Avalanches
Terms such as "unlikely", "likely", and "certain" are used to define the scale, with the chance of triggering or observing avalanches increasing as we move up the scale. For our purposes, "Unlikely" means that few avalanches could be triggered in avalanche terrain and natural avalanches are not expected. "Certain" means that humans will be able to trigger avalanches on many slopes, and natural avalanches are expected.

Size of Avalanches
Avalanche size is defined by the largest potential avalanche, or expected range of sizes related to the problem in question. Assigned size is a qualitative estimate based on the destructive classification system and requires specialists to estimate the harm avalanches may cause to hypothetical objects located in the avalanche track (AAA 2016, CAA 2014). Under this schema, "Small" avalanches are not large enough to bury humans and are relatively harmless unless they carry people over cliffs or through trees or rocks. Moving up the scale, avalanches become "Large" enough to bury, injure, or kill people. "Very Large" avalanches may bury or destroy vehicles or houses, and "Historic" avalanches are massive events capable of altering the landscape.

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
More info at Avalanche.org

Glide avalanches remain our main concern today, as the active glide cycle we’ve been tracking continues. Yesterday’s glide avalanche on the south side of Eddie’s was the latest in a string of glide avalanches that have been happening in busy areas. This includes glide avalanches on the front side of Sunburst, widespread active glide cracks above the entire motorized uptrack on Seattle Ridge, the southwest face of Cornbiscuit, and PMS Bowl on the southwest side of Magnum ridge just to name a few. We’ve also seen ongoing activity in Girdwood and Summit, and are just starting to see glide avalanches down in Seward. We have a glide problem on our hands.

These avalanches are large and destructive, and they are impossible to predict for a single slope. While we see this type of avalanche almost every season, all of the recent activity in high-traffic areas is not normal. This type of avalanche is nothing to mess with. Consider using alternate routes if your normal skin track or uptrack travels under an open glide crack. These are often easy to identify from afar as a gaping brown crack where the snow has started peeling down the slope, exposing bare ground. In some cases these cracks may just be starting to open up or have been buried by a few inches of snow and will be harder to identify; those will look more like a wrinkled or cracked surface. If choosing a new route is not an option, you can reduce your exposure by traveling one at a time and moving quickly when you have to cross under a glide crack. Keep this in mind while you are moving as well as when you are picking safe spots to watch partners.

Open glide crack on Cornbiscuit that was difficult to identify while on the slope. Photo: Peter Wadsworth, 01.09.2024

Avalanche Problem 2
  • Wind Slabs
    Wind Slabs
  • Aspect/Elevation
  • Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic (D4-5)
    Very Large (D3)
    Large (D2)
    Small (D1)
    Size
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Aspect/Elevation of the Avalanche Problem
Specialists develop a graphic representation of the potential distribution of a particular avalanche problem across the topography. This aspect/elevation rose is used to indicate where the particular avalanche problem is thought to exist on all elevation aspects. Areas where the avalanche problem is thought to exist are colored grey, and it is less likely to be encountered in areas colored white.

Likelihood of Avalanches
Terms such as "unlikely", "likely", and "certain" are used to define the scale, with the chance of triggering or observing avalanches increasing as we move up the scale. For our purposes, "Unlikely" means that few avalanches could be triggered in avalanche terrain and natural avalanches are not expected. "Certain" means that humans will be able to trigger avalanches on many slopes, and natural avalanches are expected.

Size of Avalanches
Avalanche size is defined by the largest potential avalanche, or expected range of sizes related to the problem in question. Assigned size is a qualitative estimate based on the destructive classification system and requires specialists to estimate the harm avalanches may cause to hypothetical objects located in the avalanche track (AAA 2016, CAA 2014). Under this schema, "Small" avalanches are not large enough to bury humans and are relatively harmless unless they carry people over cliffs or through trees or rocks. Moving up the scale, avalanches become "Large" enough to bury, injure, or kill people. "Very Large" avalanches may bury or destroy vehicles or houses, and "Historic" avalanches are massive events capable of altering the landscape.

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
More info at Avalanche.org

Easterly winds picked up overnight, making a fresh round of wind slabs to watch out for today. The wind is expected to switch to the southwest and calm down today, so the challenge will be to look for and avoid steep terrain that was loaded by last night’s winds. The most problematic terrain will be steep upper-elevation slopes just below ridgelines, steep convex rollovers, and cross-loaded gullies. It shouldn’t take much time to gather some information about how reactive these wind slabs will be today. Take a second to hop off your snowmachine or step off the skintrack and see what the snow on the surface feels like. If you’re seeing a relatively stiffer layer of snow on the surface sitting on top of a relatively softer layer, look for more sheltered terrain. Small but steep test slopes can be a great way to see how reactive this most recent round of wind slabs are today. Any clear signs like shooting cracks or recent avalanches should be taken as a warning that conditions are especially dangerous. Keep in mind, you won’t always get this kind of clear feedback even when conditions are reactive. If you are planning on getting into steep terrain, it’s important to take the time to poke around and see how the snow on the surface is behaving.

Additional Concern
  • Persistent Slabs
    Persistent Slabs
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
More info at Avalanche.org

We are still tracking the weak layer of near-surface facets and surface hoar that formed at the end of December and was buried right at the beginning of January. This layer produced some big avalanches during last weekend’s storm, as well as one human-triggered avalanche the day the storm finished. That avalanche was triggered remotely from a flat ridgetop above Main Bowl on the back side of Seattle Ridge. As far as we know this has been the only human-triggered avalanche on that layer, and we are thinking it is unlikely anyone else will be able to trigger an avalanche on it at this point. However, buried surface hoar layers like the one that produced that avalanche can remain reactive on isolated slopes so we are still gathering data on this layer before we drop it from the forecast entirely. Areas like Johnson Pass, Lynx Creek, or Silvertip Creek are a few zones where we have little or no snowpack data, and places where you might want to travel a bit more cautiously and be thorough with snowpack assessment before getting into steep terrain.

Weather
Sun, January 14th, 2024

Yesterday: Skies were partly to mostly cloudy with light snow showers in the afternoon that brought a trace of snow. Temperatures were in the high teens to upper 20s F yesterday morning, warming through the day and overnight into the mid 20s to low 30s F. Winds were light out of the east for most of the day, increasing to 10-20 mph with gusts of 20-40 mph overnight.

Today: We may see some lingering snow showers this morning that shouldn’t amount to any accumulation. Skies will be partly to mostly cloudy, with clouds starting to break up later in the day. Winds should be light out of the southwest at 5-10 mph with gusts of 10-20 mph. Temperatures will slowly drop today through tonight, hanging in the mid 20s F during the day and dropping to the single digits to low teens F overnight.

Tomorrow: Skies are expected to start clearing for most of the week starting tomorrow as we switch to a northwesterly flow. Temperature will be in the mid teens F with light northwesterly winds at 5-10 mph. No precipitation is expected.

PRECIPITATION 24-hour data (6am – 6am)

Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 26 0 0 85
Summit Lake (1400′) 27 0 0 35
Alyeska Mid (1700′) 26 tr tr 85
Bear Valley – Portage (132′) 33 1 0.2
Grouse Ck – Seward (700′) 31 0 0 50

RIDGETOP 24-hour data (6am – 6am)

Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 18 E 12 36
Seattle Ridge (2400′) 21 SE 7 21
Observations
Recent Observations for Turnagain Pass
Date Region Location
02/24/24 Turnagain Observation: TinCan Backdoor/ Center Ridge
02/22/24 Turnagain Avalanche: Lynx Creek
02/22/24 Turnagain Observation: Turnagain, Seattle, Mt Ascension
02/21/24 Turnagain Observation: Tincan Trees
02/21/24 Turnagain Observation: Sunburst
02/20/24 Turnagain Avalanche: Tincan
02/20/24 Turnagain Observation: Seward Highway across from Johnson Pass TH
02/19/24 Turnagain Avalanche: Base of Seattle Ridge
02/18/24 Turnagain Observation: Lynx creek
02/18/24 Turnagain Observation: Tincan Trees
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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.