February 13, 2017

Issued Monday, February 13, 2017 at 9am

Avalanche Danger Update

*Very Dangerous Avalanche Conditions*

Travel in avalanche terrain is not recommended: natural avalanches are likely, and human triggered avalanches are very likely.

Strong wind, precipitation (snow and rain), and warm temperatures have increased avalanche danger.  Avalanche danger is expected to remain elevated through the week.


Natural avalanches triggered in the upper elevations have the potential to run into lower elevation, even flat, terrain.  Many popular trails in Chugach State Park cross dangerous avalanche paths (e.g. Powerline, O’Malley Gully, Falls Creek, Rabbit Creek, South Fork Eagle River, Penguin Ridge, Iditarod-Crow Pass).  A basic level of avalanche awareness, such as that gained through a free or low-cost class, will help you be able to identify problem areas.

Acknowledge increased danger from wind, precipitation, and warmer temperatures.  Recognize red flags.  If you do go out: be on the lookout for recent avalanches.  “Whumphing,” or collapsing, and shooting cracks are glaring red flags.  Be mindful of terrain traps, and exposure to overhead avalanche danger.

Don’t forget your (fully operational) beacon, shovel, probe, and (most importantly) BRAIN!


Strong wind, precipitation (relatively wet snow, and possibly rain), and warm temperatures (possibly above freezing even at alpine elevations) are stressing a Chugach State Park snowpack with a serious persistent slab problem: thick hard slabs above basal facets and depth hoar at the ground are still failing with energy and exhibiting propagation propensity in snowpit tests.  The last significant weather event (strong winds January 30-31) initiated the most intense natural avalanche cycle in Chugach State Park in the past half decade.

There is also a well-preserved layer of buried surface hoar that has been identified in a few areas, and is possibly widespread.  This surface hoar was buried and preserved by the February 9-10 snowfall that accumulated with light wind.  It has likely created another persistent weak layer in areas where new snow and wind loading has created a slab above it.


When avalanche danger does subside, it will be important to approach the mountains with caution: careful snowpack evaluation, cautious route-finding, conservative decision-making, and effective terrain management will be essential.


Check the prior advisory and recent observations for more information and details.

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