Sun, March 02, 2014 Turnagain Pass Avalanche Forecast

Sun, March 2nd, 2014

Alpine

Above 2,500'

2 - Moderate

Treeline

1,000'-2,500'

1 - Low

Below Treeline

Below 1,000'

1 - Low

0 - No Rating

1 - Low

2 - Moderate

3 - Considerable

4 - High

5 - Extreme


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. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential.	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 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 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 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	Observer
10/27/24	Turnagain	Observation: Tincan	Michael Kerst
10/21/24	Turnagain	Observation: Turnagain Pass Road Observation	Trevor Clayton
10/19/24	Turnagain	Observation: Tincan – Below Todds Run	Andy Moderow
10/18/24	Turnagain	Observation: Taylor Pass	Eli Neuffer
10/15/24	Turnagain	Observation: Tincan Common	John Sykes Forecaster
10/14/24	Turnagain	Avalanche: Tincan	CNFAC Staff
05/13/24	Turnagain	Observation: Eddie’s, Sunburst, Seattle, Cornbiscuit, Pete’s South	H Thamm
05/13/24	Turnagain	Observation: Turnagain Pass non-motorized side	Amy Holman
05/12/24	Turnagain	Observation: Warm up Bowl	Tony Naciuk
05/07/24	Turnagain	Observation: Turnagain Pass Wet Slabs	A S

Riding Areas

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