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
Thu, January 1st, 2015 - 7:00AM
Expires
Fri, January 2nd, 2015 - 7:00AM
Forecaster
Graham Predeger
The Bottom Line

The avalanche danger is  MODERATE  today at and above treeline.  Specific terrain features such as steep, unsupported slopes or cross-loaded gullies are the most likely areas to trigger a stubborn wind slab 2 feet or more in depth.   With persistent weak layers still present in the mid-pack, a wind slab today also holds the potential to step down into one of these layers and could conceivably propagate across steep terrain.

We are back to No Rating below treeline (<1,000′) as there is not sufficient snow at this elevation band to warrant a danger rating.

Thanks to our sponsors!
Thu, January 1st, 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
  • Wind Slabs
    Wind Slabs
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.
More info at Avalanche.org

Sunday afternoon through Tuesday evening brought a warm and windy storm to the core advisory area scouring many ridges of snow, and building dense wind slabs on leeward slopes.  With ridge top winds predominantly from the East, expect West-facing slopes, particularly in the alpine to have that dense, pillowy look, indicative of wind slab (see photo below).  The steeper the terrain today, the more likely you will be to find and trigger a wind slab.  Likely trigger points include areas where the slab thins or near rock outcroppings.  It’s important to keep in mind when dealing with this avalanche problem that wind slabs are notorious for luring skiers well onto a slope before failing, often times above a skier. 

At treeline elevations winds were quite erratic during this storm so expect wind slabs to have formed on a variety of aspects.  It’ll be time well spent today to seek out small test slopes (with zero consequences) on your skin up toward alpine and jump on these hollow-sounding slopes to see how the snow reacts to a skier’s weight.

All signs are pointing toward a storm layer that will stabilize relatively quickly but as always, it’ll be prudent to pay attention to any red flags the snowpack is giving us and practice safe travel protocol both on the ascent and decent today.

Notice the difference in texture between a wind-scoured ridge (safer travel option) and a wind-loaded slope where the slab exists.

Avalanche Problem 2
  • 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

Though it’s been a full two weeks since we saw peak avalanche activity on a buried surface hoar layer in the Turnagain zone, it’s still proving reactive in snow pit tests.  This last storm added significant weight to these weak layers where wind slabs formed (though not uniform across the landscape), but judging by the lack of natural avalanche activity yesterday it doesn’t appear to have definitively tipped the stress vs. strength balance. Currently dormant in terms of avalanches, the nature of a persistent weak layer is such that it can return to a state of activity as more stress (weight) is added and thus we’ll continue to track and test these buried weaknesses as we ski into a new year.

Weather
Thu, January 1st, 2015

Yesterday was a relatively mild day across the forecast area as the most recent storm ended rather quickly Tuesday night/ Wednesday morning.   Winds dropped off precipitously with a 24-hour average of only 5mph on Sunburst and temperatures hovering around the freezing mark at 1,000′ under mostly cloudy skies yesterday.   Turnagain pass saw just a trace of snow with a few lingering rain showers in the Girdwood Valley during the afternoon hours.

Today will mark the beginning of a pattern change in south-central Alaska as we transition into northern flow.   This boils down to clearing skies and temperatures slowly dropping throughout the day to the mid to high-20’s at 1,000′ before falling significantly overnight.   With this change in flow direction we can also expect a NW wind to kick up in the 18-33mph range at ridge top levels.    No snow accumulation is expected today or throughout the weekend as temperatures continue to drop.   By Saturday, high temperatures are only expected to reach the single digits under mostly sunny skies.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 32    Trace  .1  35
Summit Lake (1400′) 30   0    0  7
Alyeska Mid (1700′) 33    0  .01  26

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′)  26  variable  5 23  
Seattle Ridge (2400′)  27  ESE 7    20
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.