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ARCHIVED - Forecasts expire after 24 hours.
Issued
Sun, March 2nd, 2014 - 7:00AM
Expires
Mon, March 3rd, 2014 - 7:00AM
Forecaster
Wendy Wagner
Avalanche risk The Bottom Line

An overall  LOW  avalanche danger this morning will rise to MODERATE on southerly aspects above treeline with daytime heating. Wet loose snow avalanches will be possible to trigger on steep slopes where the sun is able to soften surface crusts. Additionally, cornices continue to deserve a wide berth from both ridgelines and below.

Special Announcements
  • Due to warm temperatures, rain, and a decreasing snowpack all motorized areas in the Seward District and 20 mile are now closed.  The only areas open for snowmachine riding are Turnagain Pass, Johnson Pass north, Placer and Skookum. See the ‘riding conditions’ update on the bottom of this page for more details.
  • If you recreate in Turnagain Pass please consider participation in this survey at  http://edu.surveygizmo.com/s3/1523144/Avy.  Your feedback will help assist in avalanche forecasting and avalanche education while contributing to ongoing research that benefits the backcountry community.  Participants will be entered into a prize drawing and have access to final results!
Sun, March 2nd, 2014
Alpine
Above 2,500'
2 - Moderate
Avalanche risk
Treeline
1,000'-2,500'
1 - Low
Avalanche risk
Below Treeline
Below 1,000'
1 - Low
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
  • 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

Our unusual winter continues as we enter March in a melt-freeze cycle. A variable, yet mostly supportable, crust covers the snowpack as high as 4,000′ and higher in some areas. With the intense sunshine yesterday, south facing slopes were able to soften – to some degree – and this should be the case again today. No avalanche activity was seen or reported yesterday.

If you are headed out in search of sunshine and softening crusts, keep an eye out for soft snow that becomes several inches deep or more. In this case, wet loose avalanches will be possible to initiate on steep slopes. Though these are fairly slow moving and predictable avalanches, they can have a lot of mass and momentum behind them. Keeping this in mind with your terrain selection will be key. Even a small wet loose avalanche can be dangerous in terrain traps, channeled terrain, cliffs, etc.

Avalanche Problem 2
  • 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

Cornice falls continue to be a concern with our spring-like temperatures and increasing sunshine. Give cornices a wide berth and steer clear from underneath. They are notorious for breaking further back than expected.

Additional Concern
  • 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

At elevations above 2,000′ there is a variable facet/crust combination that sits 1-3′ below the surface. It has been 2-3 days since any slab avalanche activity has been reported at this interface. This activity was in the Placer valley zone and not in the heart of Turnagain Pass. Though the snowpack is tired and the facets are not proving to be very reactive, it is worth noting for those that may be headed out to the far reaches of our advisory area. This is an outlier concern that is mainly confined to >4,000′ in elevation or on steep south slopes that become very soft with the daytime warmth.

Weather
Sun, March 2nd, 2014

It was a beautiful day in the backcountry yesterday with sunny skies and calm winds. During the past 24-hours temperatures have averaged around 32F on the ridgetops and winds have been light and variable. The last precipitation was recorded on February 26/27 where 0.2″ of rain fell up to 4,000′. Side note:  The combination of very little wind and intense sun can cause temperature sensors to warm up and record inaccurate readings – this occurred at Sunburst yesterday  where a spike of 50F was recorded mid-day even though the true temperature was ~30-35F.  

Another round of clear skies is on tap today. Ridgetop winds have shifted overnight to a Northerly direction and will pick up slightly to the 10mph range. Temperatures will remain near 32F on the ridgetops and climb to ~45F at 1,000′.

Monday temperatures will begin to drop as a cold front slides in with a chance for an inch or two of snow on Tuesday into Wednesday.

Webcam junkies:
If you have not done so already – be sure to bookmark this RWIS site for Turnagain Pass. Thanks to the AK DOT who are currently getting the weather station back up and running (not all data is up yet). And a special thanks to Matt Murphy (AK DOT Avalanche Program Director and former CNFAIC forecaster) for programing in views of Eddie’s, Tincan, Seattle Ridge and the new snow stake!

Seattle Ridge (left) and Tincan (right) webcam images from 3/1
   

Observations
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
Riding Areas

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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.