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
Wed, February 20th, 2013 - 7:00AM
Expires
Thu, February 21st, 2013 - 7:00AM
Forecaster
Kevin Wright
The Bottom Line

The blizzard overnight dropped enough snow to raise the danger rating in some areas today.   Weather stations are showing 24 hour snow totals ranging from a couple inches in Summit lake, to 10 to 12 inches at Grandview.   Turnagain Pass and Girdwood got at least 8 inches at mid elevations.  

The danger rating has risen to CONSIDERABLE above treeline where storm snow and wind slab is deep enough to be a problem.   Tender wind slab at high elevations may be the most likely problem today, but we have recently seen deeper avalanches fail both at a 3 week old crust interface and full depth to the ground.

Thanks to our sponsors!
Wed, February 20th, 2013
Alpine
Above 2,500'
Considerable (3)
Avalanche risk
Treeline
1,000'-2,500'
Moderate (2)
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
Moderate (2)
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
  • Storm Slabs
    Storm Slabs
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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

Storm snow combined with wind overnight with gusts to 70 mph will make dangerous avalanche conditions in higher elevation terrain.  Today, as the snowfall continues to build, we can expect wind slabs 1-2 feet deep to be reactive to human triggers.  It may be difficult to travel above treeline due to poor visibility…

Below treeline, a low to moderate danger exists today.  Some areas in the trees that are more prone to wind loading may have shooting cracks and small reactive wind pillows.  Larger runouts are worth avoiding today until the new snow has time to settle.

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

The persistent slab is the enigma that is keeping us on our toes.  Despite the old age of these weak layers, they remain active on an infrequent basis.  Two specific issues are at play right now –

1.  A crust formed in late January is now 2-6 feet deep.  There was a report of a slide, possibly on this layer in Junior’s bowl on Seattle ridge earlier this week.  This layer seems to be a problem only at a focused elevation band between 1900 and 3000 feet, which is mid-elevation for most of our local mountains.

2.  The old October/November facets that have been dormant for the past 6-8 weeks finally showed themselves at Carter lake on Monday.  A snowmachine triggered avalanche slid to the ground on a south facing slope, narrowly missing people watching at the bottom and damaging a couple sleds that were parked. This problem is more likely to be found in the central portion of the Kenai peninsula where the snowpack is thinner and the deeper layers are more easily influenced by the weight of a person or snowmachine.

Weather
Wed, February 20th, 2013

The blizzard warning overnight seemed to bring more snow to Grandview than to Girdwood or Turnagain Pass.   Snowfall is likely more than a foot in some areas over the last 24 hours, with an average closer to 8 inches.   It is still snowing as of 7am this morning.   Wind peaked around 5pm last night and gradually diminished.   Gusts are still reaching into the 30s, which is ideal to move snow around and create wind slabs and cornices.   Temperatures rose from the single digits yesterday morning to the mid to high 20s today.

3-6 inches snow is expected today, with continued moderate to high wind.   Precipitation should remain as snow to sea level.


Graham will issue the next advisory on Thursday, February 21st.

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 Fri, May 01st, 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
Closed as of May 1. Thanks for a fun, safe season!
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.