Turnagain Pass Avalanche Forecast RSS

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ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Wed, January 26th, 2022 - 7:00AM
Expires
Thu, January 27th, 2022 - 7:00AM
Forecaster
Wendy Wagner
Avalanche risk The Bottom Line

The avalanche danger is MODERATE on all aspects above 1,000′. Triggering a lingering wind slab or a new wind slab from today’s moderate east wind, is possible. The older wind slabs are generally 1-2′ thick and could be fairly stubborn. Any new wind slab should be shallow and may only form along the higher peaks/ridges. Also, in the high elevations, there is a small chance of triggering a larger avalanche that breaks deeper in the snowpack. Lastly, be sure to give cornices a wide berth when traveling along ridgelines.

*Heavy snowfall beginning late tonight through Thursday is expected to increase the avalanche danger tomorrow. 

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Wed, January 26th, 2022
Alpine
Above 2,500'
Moderate (2)
Avalanche risk
Treeline
1,000'-2,500'
Moderate (2)
Avalanche risk
Below Treeline
Below 1,000'
Low (1)
Avalanche risk
Alpine
Above 2,500'
Avalanche risk
Moderate (2)
Treeline
1,000'-2,500'
Avalanche risk
Moderate (2)
Below Treeline
Below 1,000'
Avalanche risk
Low (1)
Danger Scale:
No Rating (0)
Low (1)
Moderate (2)
Considerable (3)
High (4)
Extreme (5)
Recent Avalanches

With a little sun breaking through yesterday, we saw evidence of several more natural avalanches from the storm late Sunday night into early Monday morning. These were wind slabs and cornice falls. Most wind slabs were between to 1-2′ deep and 50-200′ wide. All activity was partially/mostly covered up by wind.

There were no known slab avalanches yesterday. There were reports of some small skier triggered sluffs.

Natural cornice falls and subsequent wind slabs (hard to see) below in Triangle Bowl on the backside of Seattle Ridge. West aspect, 3,000′ elevation. These likely released very early on Monday, Jan 24. Photo taken 1.25.22.

Avalanche Problem 1
  • Wind Slabs
    Wind Slabs
  • Almost Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic
    Very Large
    Large
    Small
    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.

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

The break between storms will be ending today. With clouds already moving in, we can expect some light snow showers (trace to an inch today – to sea level) with heavier snow late tonight and through Thursday. Storm totals by Friday morning could reach up to 18″ or more at Turnagain Pass. Ridgetop easterly winds should be on the moderate side for this snow event – 15-20mph. That said, until the snow starts accumulating, the main avalanche concerns are lingering wind slabs and cornices, any new wind slabs, and the off chance a larger slab breaks deeper in the snowpack.

Lingering Wind Slabs:  Watch for signs those wind slabs formed early Monday morning might still be reactive. Look for any cracking in the snow around you and collapsing (whumpfing). Older wind slabs are in many places – near ridgelines, on rollovers, in cross-loaded gullies. The good news is, they have been showing signs of bonding and could be stubborn to trigger.

New Wind Slabs:  With the easterly winds on the rise today, watch for any area seeing active wind loading. Winds should generally be moderate (10-15mph with gusts in the 20’s) but could be strong enough to transport snow along the higher peaks and ridges.

Cornices:  As you can see in the photo below, cornices have grown and deserve an extra wide berth when traveling along ridgelines.

Persistent Slabs – avalanches breaking deeper in the snowpack:  We are still concerned there could be another large avalanche out there that breaks above the New Year’s crust – similar to the one that occurred last week on Tincan Proper. This is a hard thing to assess as many slopes are showing a stable snowpack under the wind slabs and surface instabilities. The places that are the most suspect are in the higher elevations and where the snowpack is generally thinner, either from less snowfall, or from wind scouring over the past month.

If traveling into the larger terrain today, we have to be sure to keep our good travel habits up. This means communicating concerns with your partners, easing into terrain, exposing only one person at a time, having escape routes planned, watching your partners closely, and being able to use your rescue gear if necessary.

 

The strong winds have created some very interesting wind features, here are a couple cornices along Seattle Ridge overhanging a low angle slope. 1.25.22.

 

Looking ahead at this next round of storms, here is a quote from the NWS Recreation Forecast:  “Continual light to moderate snow is likely late Wednesday through Friday. Totals of 1 to 3 feet are possible, with higher end of that expected east of Girdwood. Winds will remain light, generally out of the east.” I’m willing to bet most readers of this advisory would be happy for some snowfall with winds on the lighter side.

 

Graphic of storm total snowfall today through Friday morning. Courtesy of the National Weather Service Anchorage.   

Weather
Wed, January 26th, 2022

Yesterday:  Cloudy/foggy skies transitions to more broken skies with some sunshine in the afternoon. A spurt of heavy snowfall occurred in the morning adding 1-3″ of new snow. At Turnagain Pass, a light freezing drizzle followed the snowfall. Ridgetop winds were light from the west and temperatures cooled from the 30’sF to the 20’sF through the day.

Today:  Cloudy skies and light snowfall (to sea level) is expected through today with heavier snowfall late tonight as the next storm rolls in. Accumulation of an inch today and 3-5″ overnight. Ridgetop winds are forecast for 10-15mph from the east today, increasing to 20mph tonight. Temperatures should remain in the 20’s at most locations.

Tomorrow:  The brunt of the storm looks to hit Thursday with heavy snowfall, 8-12″, and a rising snow/rain line to ~500′. Ridgetop winds remain moderate, 15-20mph from the east. Snow looks to continue into Friday and possibly the weekend. Temperatures should climb into the 30’s at the elevations on Thursday, but fall again into Friday.

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

Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 28 2 0.2 85
Summit Lake (1400′) 23 2 0.2 33
Alyeska Mid (1700′) 28 3 0.26 77

RIDGETOP 24-hour data (6am – 6am)

Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 20 var 6 22 (NE)
Seattle Ridge (2400′) 22 var 5 18 (SE)
Observations
Recent Observations for Turnagain Pass
Date Region Location
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Riding Areas
Updated Fri, May 13th, 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
Closed as of May 1 per Forest Plan.
Placer River
Closed
Closed as of April 25th due to insufficient snow coverage.
Skookum Drainage
Closed
Closed as of April 1st per Forest Plan.
Turnagain Pass
Open
Open. Extended opening through May 31.
Twentymile
Closed
Closed as of April 6th due to insufficient snow coverage.
Seward District
Carter Lake
Closed
Closed as of May 1 per Forest Plan.
Lost Lake Trail
Closed
Closed as of May 1 per Forest Plan.
Primrose Trail
Closed
Closed as of May 1 per Forest Plan.
Resurrection Pass Trail
Closed
Closed as of May 1 per Forest Plan.
Snug Harbor
Closed
Closed as of May 1 per Forest Plan.
South Fork Snow River Corridor
Closed
Closed as of May 1 per Forest Plan.
Summit Lake
Closed
Closed as of May 1 per Forest Plan.

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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.