Turnagain Pass RSS

ARCHIVED - Forecasts expire after 24 hours.
Mon, March 4th, 2013 - 7:00AM
Tue, March 5th, 2013 - 7:00AM
John Fitzgerald
Avalanche risk The Bottom Line

The avalanche hazard is LOW in many areas today.   The most recent round of snowfall that occured last week has shown to be well bonded to older snow surfaces in most areas.   The hazard will be MODERATE in upper elevation starting zones, below cornices and as temperatures climb above freezing at the lower elevations today.

Special Announcements

CNFAIC forecaster John Fitzgerald will be giving a free talk on avalanche awareness including the art and science of public avalanche forecasting at REI in Anchorage on Tuesday March 5, 2013 at 6pm.   Visit REI.com for more information.

Mon, March 4th, 2013
Above 2,500'
2 - Moderate
Avalanche risk
2 - Moderate
Avalanche risk
Below Treeline
Below 1,000'
2 - Moderate
Avalanche risk
0 - No Rating
1 - Low
2 - Moderate
3 - Considerable
4 - High
5 - Extreme
Avalanche risk Avalanche risk Avalanche risk Avalanche risk Avalanche risk
Travel Advice Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Dangerous avalanche conditions. Dangerous avalanche conditions. Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain.
Likelihood of Avalanches Natural and human-triggered avalanches unlikely. Natural avalanches unlikely; human-triggered avalanches possible. Natural avalanches possible; human-triggered avalanches likely. Natural avalanches likely; human-triggered avalanches very likely. Natural and human-triggered avalanches certain.
Avalanche Size and Distribution Small avalanches in isolated areas or extreme terrain. Small avalanches in specific areas; or large avalanches in isolated areas. Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. Large avalanches in many areas; or very large avalanches in specific areas. Very large avalanches in many areas.
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

While it has been several days since any significant snowfall has accumulated, recent ridgetop winds have been high enough to blow snow around and create fresh wind slabs.  Expect to encounter these slabs in upper elevation starting zones.  Be on the lookout for snow that feels hollow or looks smooth and pillowy.  These slabs will be confined to smaller pockets but will be up to a foot in depth.

Additional Concerns

Warm temperatures and sunshine helped to release several cornices in the forecast area on Saturday.  While cloud cover will help to lower the likelihood of natural cornice releases today, warm temps and recent winds will conspire to make this a real problem in the mountains today.  A cornice triggered avalanche that occurred on Magnum on Saturday is a prime example of why it is important to know what is above you when traveling up a valley.  

Loose Snow avalanches
Wet loose snow will be moving under the influence of a person’s weight today.  Avoiding steep terrain as the snow surface becomes more damp will be the best way to avoid this problem.   This problem will be more pronounced in the lower elevations.

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

A weak layer of snow sitting on a crust at the mid elevations (1,500′-3,000′) continues to be a concern.  This weak layer/crust combo is buried 2-6 feet deep and has shown to be less of a problem on Turnagain Pass but more pronounced in outlying areas such as Summit Lake and the Girdwood, 20 Mile and Placer Valleys.   With rising temperatures this interface is more of a concern, as it will become easier for a person or snowmachine to affect these deeper layers.  As with all of the concerns today, pay attention to the thermometer and back off steep terrain as things warm up.

Mon, March 4th, 2013

The mountains around Eastern Turnagain Arm have picked up just a trace to 1″ of new snow in the past 24 hours.   Temperatures have been mild, with high 30s F at sea level, mid 20s F at 2,400′, and low 20s F at 3,800′.   The Seattle Ridge weather station has been reporting winds averaging in the mid to high 20 mph range out of the SE with gusts to 46.

Today expect mostly cloudy skies and temperatures warming to 37 degrees F at 1,000′.   Winds will be out of the SE at 5-15 mph with gusts to 20 mph.   Snowfall amounts will be very light.

The extended outlook calls for continued mild temperatures and a mix of sun and clouds for the next several days.


Wendy will issue the next advisory tomorrow morning, March 5th.

Recent Observations for Turnagain Pass
Date Region Location
11/16/23 Turnagain Observation: Tincan Common
11/14/23 Turnagain Observation: Sunburst/Magnum
11/14/23 Turnagain Observation: Seattle Ridge
11/13/23 Turnagain Avalanche: Tincan Trees
11/12/23 Turnagain Observation: Sunburst
11/12/23 Turnagain Avalanche: Goldpan – avalanche
11/11/23 Turnagain Observation: Tincan Common
11/11/23 Turnagain Observation: Taylor Pass – Sunburst
11/10/23 Turnagain Observation: Tincan
11/10/23 Turnagain Observation: Tincan Trees
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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.