CNFAIC LogoCNFAIC Logo

Avalanche Advisory

Turnagain Area Avalanche Advisory
Friday, February 1st 2013 6:09 am by John Fitzgerald
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
Previous ForecastNext Forecast
BROUGHT TO YOU BY
The Bottom Line

The avalanche hazard remains MODERATE at and above treeline, where winds will create new slabs that will be sensitive to human triggers today.  There also remains a possibility for deep slab avalanches to occur above treeline.  The hazard below treeline is LOW today where it is unlikely for avalanches to occur.


 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.
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.
Avalanche Problem 1

Wind Slabs

Light density snow that fell early yesterday morning is now being transported to form new wind slabs.  Ridgetop winds picked up overnight and are now creating slabs up to a foot in depth.  The underlying bed surfaces supporting these wind slabs vary depending on elevation.  Between 1,000 and ~2,500' these wind slabs are resting on a slick bed surface, formed by the warm temps of last week and the frigid temps of last weekend/early part of this week.  Expect to encounter the most sensitive slabs at the upper end of this elevation band, especially in open areas where the wind is blowing.  In the upper elevations wind slabs will also form and become sensitive today.  In addition, older pockets of wind slab that can cause problems are still out there as reported by a party on Magnum yesterday.

Loose snow avalanches

In wind sheltered areas above treeline expect to encounter loose snow avalanches running in steep terrain today.  While these avalanches are low in volume, the consequences increase if you're swept off your feet or machine and into terrain traps such as cliffs, trees, and gullies.


Avalanche Problem 2

Deep slabs continue to be a concern.  Weak snow that formed early in the season persists beneath dense snow that fell over the holidays.  We have seen evidence of this problem diminishing greatly below 2,000'.  Above ~2,000' the weak base to the snowpack is still showing the ability to propagate across slopes and create large avalanches.  The reality is that it is very hard to initiate one of these avalanches.  The overlying slab is relatively strong and those weak layers have had time to adjust to the weight of the slabs sitting on them.  While it may seem that there are no problems on the surface, it is important to know the weather history of this season and realize that the weak snow is still there and capable of creating unsurvivable avalanches.


Mountain Weather

A relatively calm and mild day yesterday in the mountains with no precip has given way to increasing winds overnight.  Temps are in the mid to upper twenties at ridgetops and winds are currently blowing 20 mph out of the East and Southeast with gusts to 30 mph.

Expect increasing clouds today with temps remaining mild, in the mid twenties to near 30 F at ridgetops.  Winds will be out of the E and SE at 15-20mph.  Snow showers should begin this evening and continue into tomorrow.

The extended outlook calls for a continuation of unsettled weather, with snowfall amounts remaining light and temps staying mild.

_____________________________________________________________

Kevin will issue the next advisory tomorrow morning, February 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 )

AREA STATUS WEATHER AND RIDING CONDITIONS
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

Subscribe to the Turnagain Area Avalanche Advisory:

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 or questions regarding CNFAIC operations or winter recreation management, please email staff@chugachavalanche.org
© 2018 Chugach National Forest Avalanche Information Center. All rights reserved.
FCNFAIC