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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   John Fitzgerald  
Tuesday, April 29th 2014
Created: Apr 29th 9:05 am
0 NO RATING Above Treeline
Travel Advice: Likelihood of Avalanches: Avalanche Size & Distribution:
0 NO RATING Below Treeline
Travel Advice: Likelihood of Avalanches: Avalanche Size & Distribution:
 Show the Complete North American Avalanche Danger Scale
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The Bottom Line

We are no longer issuing daily avalanche advisories for 2013/14; however, this does not mean that the avalanche season has ended - see below for some SPRINGTIME TIPS and SEASON SUMMARY.

We would like send out a HUGE THANK YOU to all of you who have submitted observations this year.  They are invaluable to us, and help provide more accurate information for everyone.  All of us at the forecast center have remarked on the increase in the quality of observations coming in from the public.  Thank you and please keep them coming!

Additionally, THANK YOU to all of you who have supported the CNFAIC through donations and a variety of other means. This is the foundation we continue to build upon.



We would also like to thank the Friends of the CNFAIC. We would NOT be here without their support and hard work - THANK YOU! This amazing and selfless group has a tireless passion for keeping all of us safe in the backcountry.



Last but far from least, we would like to thank the following for sharing the valuable avalanche information that helps to greatly improve our forecasts:


-Alaska DOT


-Alyeska Ski Patrol


-Chugach Powder Guides


-Alaska Railroad


-Alaska Avalanche School


-Alaska Pacific University

-Everyone else who has contributed this season


Primary Concern

SPRINGTIME AVALANCHE TIPS - Timing is everything
While many folks have already transitioned to summertime activities, there is still plenty of snow in the mountains.  On any given day conditions can range from warm and sunny t-shirt weather to cold & snowy mid winter conditions.  Being able to recognize and respond to specific avalanche concerns is key in making effective decisions in avalanche terrain.

Storm Snow & Wind Slabs


It is still possible to get significant snowfall this time of year.  Pay attention to how much new snow has fallen and what surface it is sitting on.  Is there a foot of new snow sitting on a crust?  Even without a persistent weak layer between the slab and the bed surface, it is still possible to trigger dangerous slab avalanches.  You can track new snowfall amounts by visiting the Turnagain Pass SNOTEL site.  Ridgetop stations will allow you to figure out wind direction and speed.  Knowledge of precipitation, wind and temperature data will give you a head start on your assessment before you even leave the house.

Loose Snow Avalanches

loose
Both dry and wet loose avalanches are common springtime avalanche concerns.  Pay close attention in steep terrain, especially when the sun first hits freshly fallen snow.

Cornices

cornice
We have yet to see any significant cornice falls this season.  Many slopes have large cornices looming above them.  Knowing exactly what will tip the scales is difficult.  Some factors that contribute to cornice fall are sun, heat, and new snow with wind.  Give cornices a wide berth and take measures to minimize your exposure to them.

Wet Avalanches

wet slab
Wet slab avalanches are also a possibility this time of year.  A combination of a slab, weak layer and water percolating into the weak layer is what is needed for this type of avalanche to occur.  This combination will be possible in the higher elevations or after a storm deposits a new slab and rain or sun sends water down into the snowpack.

 

Below are some ways to both anticipate and deal with the above mentioned avalanche concerns:


    •    Watch for the "shed cycle" in the higher elevations. One great way is to keep an eye on the ridgetop weather stations (click HERE). Avalanche activity often follows multiple consecutive days (usually 3) of above freezing overnight temperatures.  Careful route planning to stay out from under slopes with wet and rotten snow is essential during this period.  This process has already taken place in the lower to mid elevations and is now confined to upper elevation terrain.

    •    Once the snow has undergone the transition to a summertime pack and is freezing at night and warming during the day (the corn season), hitting the slopes early and getting off them when they become too sloppy is critical.

    •    Damp or wet snow more than 6" deep is a sign that it's time to exit the area. Following the aspects as the sun heats up the slopes over the course of the day, East to South then West, can make for great riding/skiing days ending in sunny tailgating.

    •    Keep in mind, cloud cover 'holds in the heat' and can dramatically limit overnight refreezing.  A shallow to no refreeze will not only give daytime heating a jump start on weakening the pack, but can produce less than stellar riding conditions.

    •    Beware of warm storms where rain is falling on snow, especially when rain is falling on cold dry snow. This can quickly increase the avalanche danger.


    •    Stay off of CORNICES.  When approaching from the side or above, make sure you can see where the cornice ends and the underlying terrain begins.  If you can’t see that transition area, move away from the edge.  If you find you and your group below cornices, expose only one person at a time and move efficiently through those areas.

    •    Lastly, don't forget to plan your route back to the car. Does it take you under slopes that were frozen and safe earlier in the day, but now have been cooking in the sun waiting to slide on your return?


Additional Concern

Watch out for bears!


Mountain Weather

SEASON ROUND UP: The Winter that Almost Was...

For anyone that ventured into the mountains this winter, it is no surprise that we hovered between 50 and 60% of our average snowpack for most of the season. The fact that the alders never laid down can attest to that. Accumulated precipitation, on the other hand, was typically in the 80-90 percentile thanks to significant rain up to, and over, 2,000' during October and late January. 

We had two significant thawing events mid-season: one in late January just mentioned (which subsequently melted out much of the pack and induced a very large spring-like shed cycle) and one smaller event in late February. After each of these, winter tried to return and we ended up with three Parts to our winter season. Part I was in December, before the January thaw. Part II in February, after a few cold storms deposited 2-3' of snow on top of the then frozen snowpack from January. And last, but many would say the best, Winter Part III in March. This third period began with a 5 day storm dropping 5' of snow followed by a 3+week high pressure. Steep lines were finally being ridden and snow stability was good. These Marvelous March days were quite welcome considering the previous two Parts were plagued with persistent and deep slab avalanche problems, including many close calls and remotely triggered avalanches.

Check out these avalanche maps Katie Johnston, 2014 intern, produced for the January, February and March cycles!
You can also find our detaliled Monthly Weather Charts on the Weather History link.

ADVISORY ROUND UP:

Above treeline: High - 11 days, Considerable - 41 days, Moderate - 47 days, Low - 41 days
Below treeline: High - 10 days, Considerable - 15 days, Moderate - 53 days, Low - 67 days

 

Below is NRCS's graph of the current year's Precipitation and SWE (Snow Water Equivalent) compared to the average. 



Don't be scared off by this overwhelming looking graph!! It's the past 10 years of snow depth on the Pass. Interesting to compare years.

 


January average temperature beginning 1985 (1880' elevation) - Tied for 3rd this year



Turnagain Pass's Center Ridge SNOTEL site on November 6th - No snow...

 


Remember, for current weather see the CNFAIC weather page.

Have an excellent summer and Thank You for tuning in!

 

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).

Winter snowmachine use open/closed status and riding conditions updates

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 29, 2014 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedClosed as of April 23rd.
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: Closed
Snug Harbor: OpenPlease stay on existing road (and snow) bed to gain access into Lost Lake. Snug Harbor will be closing to snowmachines on May 1st.
South Fork Snow River Corridor: Closed
Summit Lake: Closed

The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur. This advisory provided by the Chugach National Forest, in partnership with Friends of the Chugach National Forest Avalanche Information Center.


USFS SNOW AND AVALANCHE HOTLINE (907) 754-2369
If you have comments regarding CNFAIC operations or winter recreation managment, please email kevin@chugachavalanche.org
© 2014 Chugach National Forest Avalanche Information Center. All rights reserved.
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