Share your feedback! Share your feedback!

How’s our new website?
How can we better serve you?

Turnagain Pass Avalanche Forecast RSS

Archives
ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Issued
Sun, April 23rd, 2017 - 7:00AM
Expires
Mon, April 24th, 2017 - 7:00AM
Forecaster
Wendy Wagner
The Bottom Line

The avalanche danger is expected to rise to CONSIDERABLE late in the day on Sunday and into Monday. Warm temperatures continue to soften the snowpack creating a wet avalanche hazard on all slopes over 35 degrees in steepness. Natural wet avalanches may begin to release as early as this afternoon and are expected to occur on Monday. Steep and rocky slopes with a shallow snowpack are the most suspect for releasing. Human triggered wet slab and wet loose avalanches will be likely on steep slopes that have a wet, saturated and unsupportable snowpack.

Hiking on summer trails during the springtime warm-up (including the Byron Glacier trail, Crow Pass, etc).    Extra caution is advised for trails that cross under avalanche paths. Avalanches possible at the higher elevations could send debris over snow-free hiking trails.  
 

MONDAY APRIL 24th AVALANCHE OUTLOOK:
A CONSIDERABLE avalanche danger is expected for Monday. Increased warm weather conditions will enhance the possibility for natural wet avalanches on all aspects above 1,000′. Please see the discussion below for more details.

Thanks to our sponsors!
Sun, April 23rd, 2017
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)
Avalanche Problem 1
  • 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

During the springtime warm-up and the snowpack melt-down (or shed cycle), there is an ‘old-timer’ rule of thumb. This goes as follows: One can start expecting wet avalanches to begin after three consecutive nights with no re-freeze along the ridgetops. Last night was the second night without a sold re-freeze, and tonight will be the third….. 

Although many South and Southeast slopes such as Seattle Ridge have already melted down over the past 2 weeks of sunny weather (meaning significant wet avalanche activity has occurred), there are still West, North and East slopes that remain intact. Westerly and Easterly slopes are theoretically next in line. Will we start seeing the West/East aspects release this week – there is a good chance with the cloudy and warm weather forecast. So what to watch for if headed to the mountains? Is the snowpack frozen or is it mushy and wet? That’s the key.

Cloud cover: Starting last Friday night, cloudy skies have been trapping in the daytime heat and severely limiting the amount of overnight re-freeze. Although the breezy winds have helped combat this, the pack is still loosening up and becoming weaker. This trend is expected to continue with the forecasted warm, cloudy conditions. Aside from the avalanche concern – many folks have been traveling on glaciated terrain – snow bridges over crevasses are sagging and punching through is becoming more likely.

WET SLAB, WET LOOSE, GLIDE AVALANCHES and CORNICE FALLS:

These are the different characters of avalanches that occur with the melt-down or shed cycle during springtime. Things to keep in mind if headed out:

  1. Did the snowpack re-freeze overnight in your location? A hard frozen snowpack is stable, a soft mushy snowpack is dangerous.
  2. Are you punching through a shallow crust into wet soggy snow as in the photo below? Also a sign the snowpack is weak and could avalanche.
  3. Do you see any recent avalanches.
  4. Are you in a runout zone? Can an avalanche releasing above wash debris over your location? Avalanches can run into valley bottoms.
  5. Buried weak layers in the pack can make a small avalanche or sluff become bigger by propagating across the slope and/or stepping down.
  6. Wet avalanches are hard to escape if you get caught. A small slide can be deadly if it pushes you into a terrain trap.

 

Yesterday, this was the only recent avalanche noted – a small glide on the lower South face of Tincan 

 

Avalanche Problem 2
  • Glide Avalanches
    Glide Avalanches
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.
More info at Avalanche.org

Glide avalanches are still releaseing here and there – we saw one yesterday pictured above. Watch for glide cracks and avoid being under them as they can release at any time.

Additional Concern
  • Deep Persistent Slabs
    Deep Persistent Slabs
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.
More info at Avalanche.org

Upper elevation Northerly aspects warmed yesterday enough to moisten the top 4″ at 3,800′. This trend is expected to continue with the forecast warm, cloudy conditions. With the added warmth of the pack in these shaded zones, increased stress on underlying weak layers will be occurring. There are several buried persistent weak layers in the snowpack; ranging from buried surface hoar 2-6′ deep, mid-pack facets and facets near the ground. Shallow snowpack zones such as the Summit Lake area harbor depth hoar near the ground. As the snowpack warms up, these weak layers could re-activate and triggering a slab avalanche is possible. This is a low probability, high consequence problemKeep these points in mind:  

  • It will take someone hitting a ‘thin spot’ in the slab, or a large trigger such as a snowmachine and/or groups of people or a cornice fall
  • There may be no signs of instability before the slope breaks
  • Several tracks may be on a slope before it releases
  • Stability tests may not produce any notable results
Weather
Sun, April 23rd, 2017

Overcast skies and a breezy East wind were over the area yesterday. Over the past 24-hours, Easterly ridgetop winds have been averaging between 10-20mph with gusts to 30mph. Temperatures were up to 50F below 2,000′ and up to 36F along the 4,000′ ridgelines. All the precipitation, light rain, so far has stayed far to our South.

For today, Sunday, mostly cloudy skies are expected that will continue to hold in the warmth. Ridgetop winds from an Easterly direction will be in the 10-15mph range. Temperatures should stay warm, increasing with daytime warming to 50F below 2,000′ and 30-35F along ridgetops. Overnight limited cooling is expected with temperatures dropping to ~40F below 2,000′ and ~30F along ridgetops.  

For Monday: A weak low pressure moves through that will bring a chance for light rain to 2,500′. Temperature and winds are expected to remain very similar to Sunday, the main change being increased chance for light precipitation and thickening cloud cover. A series of small disturbances will continue to move through during the workweek, keeping skies cloudy and temperatures warm.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 45   0   0   59  
Summit Lake (1400′) 42   0   0   18  
Alyeska Mid (1700′) 43   0   0    53  

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 33   NE   12   30  
Seattle Ridge (2400′) No Data   SE   13   25  
Observations
Recent Observations for Turnagain Pass
Date Region Location
05/06/20 Turnagain Avalanche: Pastoral Peak, north face
04/10/20 Turnagain Avalanche: Wolverine
04/10/20 Turnagain Observation: Eddies lookers right shoulder
04/09/20 Turnagain Observation: Bench Peak
04/04/20 Turnagain Observation: Tincan
04/04/20 Turnagain Observation: Pete’s North
03/26/20 Turnagain Avalanche: Tincan – Proper (SW facing)
03/26/20 Turnagain Avalanche: Seattle Ridge
03/25/20 Turnagain Avalanche: Sunburst Uptrack @ 2000′
03/24/20 Turnagain Observation: Turnagain – Road Observations
Riding Areas
Updated Mon, October 26th, 2020

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
Placer River
Closed
Skookum Drainage
Closed
Turnagain Pass
Closed
Twentymile
Closed
Seward District
Carter Lake
Closed
Lost Lake Trail
Closed
Primrose Trail
Closed
Resurrection Pass Trail
Closed
Snug Harbor
Closed
South Fork Snow River Corridor
Closed
Summit Lake
Closed

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.