Turnagain Pass Avalanche Forecast RSS

Archives
ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Wed, March 30th, 2022 - 7:00AM
Expires
Thu, March 31st, 2022 - 7:00AM
Forecaster
Wendy Wagner
Avalanche risk The Bottom Line

The avalanche danger remains CONSIDERABLE on all aspects above 1,000′. Triggering a very large slab avalanche over 3 feet deep is possible. These slabs could be triggered remotely and could release over an entire slope creating a very large and dangerous slide. Cautious route-finding and conservative decision-making are essential.

Additionally, wet loose avalanches are likely later in the day due to sunshine and warm temperatures. Triggering a large cornice fall is also possible; remember to always give cornices an extra wide berth.

SUMMIT LAKE/LOST LAKE/SNUG:  Areas out of our forecast zone on the Kenai will also see a warm sunny day. Watch for both wet loose avalanches as well triggering a large slab.

Thanks to our sponsors!
Wed, March 30th, 2022
Alpine
Above 2,500'
Considerable (3)
Avalanche risk
Treeline
1,000'-2,500'
Considerable (3)
Avalanche risk
Below Treeline
Below 1,000'
Moderate (2)
Avalanche risk
Alpine
Above 2,500'
Avalanche risk
Considerable (3)
Treeline
1,000'-2,500'
Avalanche risk
Considerable (3)
Below Treeline
Below 1,000'
Avalanche risk
Moderate (2)
Danger Scale:
No Rating (0)
Low (1)
Moderate (2)
Considerable (3)
High (4)
Extreme (5)
Recent Avalanches

There were no reported or known slab avalanches triggered yesterday; there was also very little traffic out in the mountains. The last known slab avalanches were on Monday during the last pulse of snowfall. Yesterday, there were however some small wet loose sluffs and rollerballs when the sun poked through.

Avalanche Problem 1
  • Deep Persistent Slabs
    Deep Persistent Slabs
  • Almost Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic (D4-5)
    Very Large (D3)
    Large (D2)
    Small (D1)
    Size
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.

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

We are about to head into our first real sunny day after a week of stormy weather. This will allow for easy travel into the higher terrain and depending on how busy the mountains are, increase the number of potential triggers. For anyone headed out today, we have two main messages: 1) have a conservative mindset and 2) understand that there is the possibility of triggering a large and deadly avalanche.

The 4-6+ feet of snow that fell since last Wednesday has settled into a fairly hard slab in the 3-4′ deep range. These slab depths are shallower toward the interior Kenai and thicker near Portage and Placer Valleys. That dense slab of snow is sitting on a mixed bag of layers such as, buried surface hoar, near surface facets, and sun crusts. How well the slab is bonding is the big question. Last Saturday it was highly reactive when two skiers remotely triggered it on Pete’s North. Since then, it has been loaded by another foot of snow from Monday.

 

Settled snow from the past week of stormy weather. We saw 3.5 feet of hard settled storm snow on Sunburst around 3,200′. 3.29.22.

 

Furthermore, there are two additional layers of older buried surface another 1-2 feet below the bottom of the settled storm snow. Looking at the whole picture, these weak layer are all deep enough and appear to have the characteristics to fit into the Deep Persistent Slab category. A large slab may not be as easy to trigger now, but we still need to follow the travel advice for CONSIDERABLE danger. This is due to the potential size of a slide as well as the uncertainty of how easy one could be triggered. Characteristics of a Deep Persistent Slab avalanche:

  • No signs of instability (snow feels ‘fine’ / ‘stable’) before a slab releases
  • Avalanches could be triggered remotely (from the top, side, or below a slope)
  • Can be hard to trigger due the depth of the weak layers. Often these are triggered where the winds created thin spots in the slab.

Because this slab is essentially still untested, we need to be thoughtful and take our time getting into the bigger terrain. If choosing to push onto steeper slopes be sure to have all your safe travel protocol dialed. This is exposing one person at a time, having escape routes planned, watching your partners closely, and having the tools/skills to effect a rescue if the slope releases. The potential size of an avalanche could be so large that our safe travel protocol won’t make much difference. Debris could run further than expected and take out what we ‘think’ are safe spots. Until we have a bit more time and understanding, we can also just play it safe and avoid this high consequence situation by keeping our slope angles mellow and staying off the big terrain.

Cornices:  Cornices have grown over the past week and warm temperatures today could add to their instability. Steer well clear of cornices, they can break much further back than we might expect.

Lingering wind slabs: On top of this dense slab could be lingering wind slabs formed during Monday’s snow and wind. Hollow feeling snow and cracking in the snow around you will be signs for this type of avalanche.

 

Avalanche Problem 2
  • Wet Loose
    Wet Loose
  • Almost Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic (D4-5)
    Very Large (D3)
    Large (D2)
    Small (D1)
    Size
Wet Loose
Wet Loose avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

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

Don’t forget your sunscreen… the sun is expected to shine all day today with only light northwest winds. This should really heat up the southerly slopes, melt any surface crusts, and will likely create more rollerball and wet loose avalanche activity. There is a chance a wet loose sluff could entrain a fair amount of snow and even pop out a slab or two. Whether it could trigger a very large deep slab isn’t out of the question. It’s that time of year to watch our aspects and how much the surface snow is heating up. Avoiding steep slopes that become wet and saturated is key for the springtime warm afternoon/evenings.

Roller balls with some small wet loose avalanches on the SE face of Seattle Ridge during some periods of sun yesterday. 3.29.22. 

Weather
Wed, March 30th, 2022

Yesterday:  Clouds were in and out yesterday with some periods of sun with obscured skies. A trace of snow fell during some instability showers that developed. Ridgetop winds were 10-20mph from the east. Temperatures warmed to near 40F in parking lots and the upper 20’sF along ridgetops.

Today:  Sunshine and warming daytime temperatures are forecast for today. Ridgetop winds have swung around to the west/northwest overnight where they will remain in the 5-10mph or less range. Temperatures could rise to the upper 40’sF at the lower elevations and into the 30’sF along ridgelines.

Tomorrow:  Another storm is brewing. Ridgetop winds look to shift back easterly and increase through tomorrow (20-30mph). Light snowfall should begin midday with moderate snowfall lasting through Friday. By Saturday morning we could see around 4-8″ of new snow (rain/snow line may rise to near 500′ Friday).

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

Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 32 trace trace 119
Summit Lake (1400′) 30 0 0 41
Alyeska Mid (1700′) 34 0.5 0.05 N/A

RIDGETOP 24-hour data (6am – 6am)

Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 23 NE 10 28
Seattle Ridge (2400′) 27 N/A* N/A* N/A*

*The Seattle Ridge anemometer (wind sensor) is rimed over and not reporting data.

Observations
Recent Observations for Turnagain Pass
Date Region Location
12/07/22 Turnagain Avalanche: Tincan
12/07/22 Turnagain Observation: Eddies skintrack
12/06/22 Turnagain Observation: Seattle Ridge- Main Bowl
12/04/22 Turnagain Observation: Silvertip
12/04/22 Turnagain Observation: Kickstep Glacier
12/03/22 Turnagain Observation: Seattle Ridge
12/03/22 Turnagain Observation: Seattle Ridge
12/03/22 Turnagain Observation: Superbowl
12/02/22 Turnagain Avalanche: Magnum/Cornbiscuit
11/30/22 Turnagain Observation: Tincan
Riding Areas
Updated Wed, December 07th, 2022

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: mailroom_r10_chugach@fs.fed.us

Area Status Weather & Riding Conditions
Glacier District
Johnson Pass
Closed
The Forest has issued a closure order due to inadequate snow cover for resource protection. Conditions will be monitored daily. Scheduled opening would have been Dec 1st.
Placer River
Closed
The Forest has issued a closure order due to inadequate snow cover for resource protection. Conditions will be monitored daily. Scheduled opening would have been Dec 1st.
Skookum Drainage
Closed
The Forest has issued a closure order due to inadequate snow cover for resource protection. Conditions will be monitored daily. Scheduled opening would have been Dec 1st.
Turnagain Pass
Closed
The Forest has issued a closure order for Turnagain Pass due to inadequate snow cover for resource protection. Conditions are being monitored daily. 22” of snow exists at the parking lot. Another storm on Sunday/Monday 12/11 may just do it.
Twentymile
Closed
The Forest has issued a closure order due to inadequate snow cover for resource protection. Conditions will be monitored daily. Scheduled opening would have been Dec 1st.
Seward District
Carter Lake
Closed
The Forest has issued a closure order due to inadequate snow cover for resource protection. Conditions will be monitored daily. Scheduled opening would have been Dec 1st.
Lost Lake Trail
Closed
The Forest has issued a closure order due to inadequate snow cover for resource protection. Conditions will be monitored daily. Scheduled opening would have been Dec 1st.
Primrose Trail
Closed
The Forest has issued a closure order due to inadequate snow cover for resource protection. Conditions will be monitored daily. Scheduled opening would have been Dec 1st.
Resurrection Pass Trail
Closed
Closed to motorized use for the 2022/23 winter season per Forest Plan. Open next season.
Snug Harbor
Closed
The Forest has issued a closure order due to inadequate snow cover for resource protection. Conditions will be monitored daily. Scheduled opening would have been Dec 1st.
South Fork Snow River Corridor
Closed
The Forest has issued a closure order due to inadequate snow cover for resource protection. Conditions will be monitored daily. Scheduled opening would have been Dec 1st.
Summit Lake
Closed
The Forest has issued a closure order due to inadequate snow cover for resource protection. Conditions will be monitored daily. Scheduled opening would have been Dec 1st.

Subscribe to Turnagain Pass
Avalanche Forecast by Email

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.