Turnagain Pass Avalanche Forecast RSS

Archives
ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Mon, March 23rd, 2015 - 7:00AM
Expires
Tue, March 24th, 2015 - 7:00AM
Forecaster
John Fitzgerald
Avalanche risk The Bottom Line

The danger is MODERATE in the Alpine today, where the possibility exists for pockets of slab 2-3′ thick to be triggered on steep slopes.   While the likelihood of triggering is trending towards the low end of the scale, the consequences are high enough to injure or bury a person.   Wet loose avalanches will be higher on the likelihood scale and lower on the consequence scale, as volume will be generally low but increase on steep sustained slopes.   Cornices will feel the heat of the sun today and could release naturally.

The danger is LOW this morning at Treeline.   Daytime heating will increase the chances for shallow wet loose avalanches and nudge the danger to MODERATE in steep terrain over 40 degrees.

Special Announcements
  • The Friends of the Chugach Avalanche Center is an  official Pick. Click. Give. organization.  When you apply for your PFD please consider supporting your public avalanche center.   Every little bit helps and allows us to provide the best possible service.   Thank you to all of our donors past, present and future!
Thanks to our sponsors!
Mon, March 23rd, 2015
Alpine
Above 2,500'
Moderate (2)
Avalanche risk
Treeline
1,000'-2,500'
Moderate (2)
Avalanche risk
Below Treeline
Below 1,000'
No Rating (0)
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
No Rating (0)
Danger Scale:
No Rating (0)
Low (1)
Moderate (2)
Considerable (3)
High (4)
Extreme (5)
Avalanche Problem 1
  • 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

It has now been 5 days since the last loading event occurred.  In that time we have seen a daily cycle of melting and freezing on sunlit aspects and generally mild temps.  This pattern has helped 2-3’ slabs that formed last week to become less reactive.  In some areas these slabs are resting on a thin layer of weak faceted snow.  In areas where we have been able to find this combo, there still exists the possibility of triggering one of these slabs.  This problem is variable across the landscape, as it is not something you will find on every slope.  Digging in the snow can help you to understand the problem better, but could also be misleading.  

How do we manage this uncertainty?  By using effective terrain management techniques.  Only expose one person at a time on suspect slopes, use islands of safety for spotting and re grouping, and identity escape routes.

Recent slab avalanche at 3,500′ W aspect.  Debris pile visible left of center coming out of the shadow. 

Slab at head of Ingram Cr

Avalanche Problem 2
  • Wet Loose
    Wet Loose
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.
More info at Avalanche.org

The more likely avalanche concern today will be wet loose avalanches.  These will be generally low in volume and are easy to anticipate.  Volume will increase on steep sustained slopes.  As the days get longer, so does the amount of terrain that the sun affects increase.  Steep slopes being impacted by direct sunshine will continue to shed shallow loose snow avalanches.  Several natural wet loose avalanches that triggered shallow wet slabs were observed in the Girdwood Valley yesterday.  More of the same is possible today.

Pay attention to the snow surface on sunlit aspects today.  As your skis or board begin sinking more than several inches it will be important to begin dialing back slope angles.

Additional Concern
  • Cornice
    Cornice
Cornice
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.
More info at Avalanche.org

Cornices grew significantly with last week’s storms.  Direct sun and a lack of wind will help to weaken these features.  As always give cornices a wide berth.  Minimize time spent underneath and make sure you can see the profile before approaching any corniced ridges.

Weather
Mon, March 23rd, 2015

Yesterday brought abundant sunshine under clear skies.   Temps were mild and winds were generally calm.   No new precipitation was recorded.

Today looks to be a carbon copy of yesterday, with slightly warmer temps.   Temperatures will reach into the low 40s F at 1,000′ and near 32 F along ridgetops.   Winds will be calm and skies will be clear.

High pressure stretching from Southeast Alaska through Southcentral and into the interior will prevent a low pressure system centered over Bristol Bay from impacting the area.   This pattern looks to break down by mid week as we return to warm and wet Southerly flow.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 33 0 0 55
Summit Lake (1400′) 30 0 0 12
Alyeska Mid (1700′) 35 0 0 32

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 27 var 4 14
Seattle Ridge (2400′) 29 var 4 15
Observations
Recent Observations for Turnagain Pass
Date Region Location
05/22/23 Turnagain Avalanche: Tincan
05/12/23 Turnagain Avalanche: Tincan, Sunburst, Magnum, Cornbiscuit
05/07/23 Turnagain Observation: Tincan – Bear Tracks
05/05/23 Turnagain Observation: Seattle Ridge
05/02/23 Turnagain Observation: Cornbiscuit
05/02/23 Turnagain Observation: Seward Hwy Turnagain Pass
04/30/23 Turnagain Observation: Magnum
04/29/23 Turnagain Observation: Tincan
04/28/23 Turnagain Avalanche: Taylor Pass/Pastoral
04/28/23 Turnagain Avalanche: Tincan
Riding Areas
Updated Thu, June 01st, 2023

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 May 15.
Placer River
Closed
Closed May 15.
Skookum Drainage
Closed
Will close to motorized use on April 1, 2023 per the National Forest Plan.
Turnagain Pass
Closed
Will close on June 1.
Twentymile
Closed
Scheduled closure May 1.
Seward District
Carter Lake
Closed
Scheduled closure May 1.
Lost Lake Trail
Closed
Scheduled closure May 1.
Primrose Trail
Closed
Scheduled closure May 1.
Resurrection Pass Trail
Closed
Closed to motorized use for the 2022/23 winter season per Forest Plan. Open next season.
Snug Harbor
Closed
Extended opening until May 15.
South Fork Snow River Corridor
Closed
Scheduled closure May 1.
Summit Lake
Closed
Scheduled closure May 1.

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.