Avalanche Advisory

Turnagain Area Avalanche Advisory Sunday, December 11th 2016 5:41 am by Heather Thamm ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.

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A generally LOW avalanche danger exists across all elevations bands for the Turnagain Pass zone. Triggering a 1-2' avalanche is unlikely but not impossible. The most suspect slopes are in steep terrain at the high elevations where someone just might be able to break off an old wind slab or find a slope with the buried surface hoar that hasn't slid. Good travel habits, such as exposing one person at a time, watching your partners and grouping up in safe zones are key ways to minimize risk. Ease onto steep slopes and be prepared to change your plans if an area becomes too crowded.

There is snow to sea level, just enough to put a LOW danger rating on the Below Treeline Elevation band. If venturing into the 'periphery' forecast zones, such as Girdwood Valley, more caution is advised due to limited information about the snowpack in these areas. This should also be part of the equation if you are heading to ice climb in Portage where even a small slide could have high consequences.

If headed to Summit Lake check out the Saturday Summit Lake Summary HERE. 

Show the Complete North American Avalanche Danger Scale

North American Public Avalanche Danger Scale Avalanche danger is determined by the likelihood, size and distribution of avalanches. Danger Level Travel Advice Likelihood of Avalanches Avalanche Size and Distribution 5 Extreme Avoid all avalanche terrain. Natural and human- triggered avalanches certain. Large to very large avalanches in many areas. 4 High Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. Natural avalanches likely; human- triggered avalanches very likely. Large avalanches in many areas; or very large avalanches in specific areas. 3 Considerable Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential. Natural avalanches possible; human- triggered avalanches likely. Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. 2 Moderate Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Natural avalanches unlikely; human- triggered avalanches possible. Small avalanches in specific areas; or large avalanches in isolated areas. 1 Low Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Natural and human- triggered avalanches unlikely. Small avalanches in isolated areas or extreme terrain. Safe backcountry travel requires training and experience. You control your own risk by choosing where, when and how you travel.

1 Low Alpine / Above 2,500'

Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1 Low Treeline / 1,000'-2,500'

Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1 Low Below Treeline / Below 1,000'

Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Yesterday an observer reported Alaska State Troopers enforcing parking distances from the road cooridor at the Seattle Ridge snow stake/DOT Weather Station. Please make responsible parking choices at trailheads and consider going to an alternative area if no spots are available. 

Mark your calendar for next week's Fireside Chat: Avalanche Awareness and Rescue w/CNFAIC in Girdwood at the Powder Hound Ski Shop! December 15 @ 6:30 pm - 8:00 pm. FREE.  

The Friends of the CNFAIC is offering two $500 avalanche scholarships through the Rob Hammel fund. One is for avalanche professionals and the other is open to anyone!  The deadline for both scholarships is Dec 15th! For more information click this link HERE. 

Avalanche Problem 1

Remember LOW hazard doesn't mean NO hazard! Yesterday lots of slope tester were observed and there were no human triggered avalanches reported. With a stable weather pattern dominating our region and very little changes affecting the snowpack we are in a Normal Caution phase for avalanche issues. These include:

1- Triggering an outlier avalanche. This would most likely be an 'unsupported slab' that sits above a cliff or steep rocky terrain. More on this below in ‘Additional Concerns.’

2- Triggering an old wind slab - Avoid hard stiff snow sitting in steep rocky terrain where a small isolated wind slab could have high consiquences.  

3- Triggering a cornice fall. Cornices maybe be small right now, but similar to wind slabs they could take you down somewhere you don't want to go. Give cornices a wide berth.

4- Sluffs on steep slopes. Small sluffs were observed yesterday, and as the surface snow becomes weaker under clear skies the potential for bigger stuff will increase. 

Thin snow cover, limited access and high volumes of people will add another degree of challenge for making safe decisions. Before commiting to a route in steep avalanche terrain ensure that you are only exposing one person at a time. In places where you can not see the entire slope this may not be possible. Be prepared to change your objectives if an area becomes too crowded to manage.

An example of the crowds from yesterday, 15 people on the skin track on a SW aspect of Magnum. 

Even with LOW avalanche danger it is still important to remember the weak layer 1-2' below the surface i.e. the notorious Nov 16th buried surface hoar. Although we have not seen an avalanche release in this layer since last Saturday and the slab character has been changing due to the cold temperatures, there are many slopes away from the 'popular' zones that have yet to be tested. These are the areas most suspect over the weekend. Finding the spot that harbors this weak layer, still has a slab, and hasn't been skied or slid already still could be dangerous... Triggering is unlikely but not impossible!

Yesterday skies were clear with thick valley fog rolling in/out of Turnagain Arm. Temperatures were near zero (F) at lower elevations and in the alpine temperatures average around 15F. Winds were light and variable and no precipitation was recorded. 

Today looks very similar with slightly warmer temperatures, 15F-25F with a slight temperature inversion in the alpine. Winds are expected to remain light from the NW and no precipitation is expected.

Cold arctic air sitting over mainland, Alaska will continues to dominate our weather pattern over the next few days. The next chance for a pattern change/possibility of precipitation will be later in the week.

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

RIDGETOP 24-hour data (6am - 6am)

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).

Riding status is not associated with avalanche danger. An area will be open to motorized use in accordance to the Forest Management Plan when snow coverage is adequate to protect underlying vegetation. Backcountry hazards including avalanche hazard are always present regardless of the open status of motorized use areas.

(Updated: Apr 20, 2018 )

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