Avalanche Advisory

Turnagain Area Avalanche Advisory
Monday, April 1st 2013 5:29 am by John Fitzgerald
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

The avalanche hazard is LOW this morning and will rise to MODERATE above and below treeline as the temperatures rise.  Wet loose/wet slab avalanches and cornices will be the main concerns today.

 Show the Complete North American Avalanche Danger Scale
2 Moderate Alpine / Above 2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
2 Moderate Treeline / 1,000'-2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
2 Moderate Below Treeline / Below 1,000' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Special Announcement

The Skookum drainage is now closed to motorized travel for the remainder of the season.

Avalanche Problem 1

When figuring out how weather influences avalanches, we need to look at three main factors: precipitation, temperatures, and wind.  Today temperatures will be the factor to pay the most attention to.  Closely related to temp, and requiring your attention today, will be the sun.  We have begun a melt freeze cycle around here.  While this is a trend that generally encourages the stabilization of the snowpack, there is a critical period during the day when the snowpack de stabilizes.  It's during these times when it is important to move off of terrain to avoid avalanches.  Paying attention to the surface snow and how deep your sled or skis penetrate is the best tool for recognizing this hazard.  The further you are sinking in, the greater the volume of an avalanche will be.  Looking for rollerballs and pinwheels is another way to anticipate wet avalanche activity.  We received mutlple reports of natural wet avalanches in the mid and lower elevations yesterday.  Both the sun and ambient air temp will help to weaken the snow surface and allow for humans to trigger low to medium volume wet loose and potentially wet slab avalanches today.

Avalanche Problem 2

These giant masses of snow dangling above many South, Southwest and some West facing slopes will be tested by the sun and warm temperatures today.  Today is not your day to tempt fate.  While it will be easy to figure out what is happening when you are near cornices (i.e. on ridgelines), it is a whole other story when that cornice is a thousand or more feet above you.  When traveling up valleys today it will be best to treat any slope receiving direct sunlight with suspicion.  Having groups spaced out to minimize exposure and not stopping directly below cornices, even if they seem far away, will be your best way to manage this problem today.


Additional Concern:

(Old) Wind Slabs

There remains a chance for finding a lingering pocket of wind slab in steep upper elevation starting zones today.  Wind slab avalanche activity peaked on Friday/Saturday, over two days ago, and remains a (lower level) concern.

Mountain Weather

In the past 24 hours the mountains around eastern Turnagain Arm have experienced warm temperatures, with the Sunburst weather station (3,812') averaging 22.6 degrees F and the freezing level climbing to the ~2,500' elevation.  Winds at Sunburst have been light, averaging 3mph out of the East with gusts to 12mph.  Precip ended in the morning hours yesterday and totaled 6" of snow in the Girdwood Valley and just a trace on Turnagain Pass.

Today expect a similar day to yesterday, with rising temperatures and sunlight being the main weather factors to incorporate into your terrain selection.  Temperatures at 1,000 feet will be in the 35-40 degree range.  Winds out of the north will be light, in the 5 to 10 mph range and will minimally help to lessen the effects of the sun and warm temps today.

The extended outlook calls for continued mild temperatures, sunshine and no precip until the end of the week.


Wendy will issue the next advisory tomorrow morning, April 2nd.

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: May 06, 2018 )

Glacier District
Johnson Pass: ClosedClosed as of April 20th
Placer River: ClosedClosed as of April 17th
Skookum Drainage: ClosedClosed as of April 1st.
Turnagain Pass: ClosedClosed as of May 7th. Happy summer, see ya when the snow flies!
Twentymile: ClosedClosed as of April 13th
Seward District
Carter Lake: ClosedClosed as of 4/27
Lost Lake Trail: ClosedClosed as of April 13th
Primrose Trail: ClosedClosed as of April 13th
Resurrection Pass Trail: ClosedClosed as of April 20th
Snug Harbor: ClosedClosed as of 4/27
South Fork Snow River Corridor: ClosedClosed as of April 13th
Summit Lake: ClosedClosed as of April 20th

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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.

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