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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   John Fitzgerald  
Monday, March 10th 2014
Created: Mar 10th 6:18 am
3 Considerable Alpine / Above 2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
3 Considerable Treeline / 1,000'-2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
3 Considerable Below Treeline / Below 1,000' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
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The Bottom Line

The avalanche hazard will be on a quick rise today.  This morning the hazard is LOW at all elevations.  New snow and wind will bump the hazard to CONSIDERABLE by the end of the day, as a winter storm impacts the area.  Snowfall amounts in the 10” to 14” range will create slabs that will be very sensitive to human triggers and could release naturally.


Primary Concern

Over the past several days we have been mapping the snow surface.  A consistent theme around the forecast zone is a thin layer of weak snow sitting on a crust.  This set up by itself is not a concern.  Today that all changes as a slab will be sitting on this weak interface by the end of the day.



Snowfall amounts (and intensity) on their own will be enough to create unstable conditions.  In areas where this slab/weak layer/crust combo exists, the snow will be very unstable.  Avalanche terrain at all elevations will become more prone to activity as the new snow accumulates.  As snowfall amounts begin pushing past the 6-8” range, it will become more likely for slabs and loose snow avalanches to occur naturally.  Be on the lookout for obvious signs of unstable snow: recent avalanches, shooting cracks, & collapsing/whoompfing.  If you start seeing any of these signs, it is time to scale back on terrain choices.

In favored locations and wind loaded areas slabs could grow into the 2 foot range.  All slopes above 35 degrees or in the runout of terrain above should be avoided as slabs increase in depth throughout the day.


Mountain Weather

In the past 24 hours ridgetop temperatures have averaged in the high teens F.  Winds have picked up overnight and are currently 24 mph at the Sunburst station, 17 mph at Seattle Ridge, and 22mph at Alyeska (Max’s) out of the East.  Clouds moved in overnight as the leading edge of a storm made its way into the area.

Winter part 3 has arrived!

A strong Low pressure system South of the Alaska Peninsula is moving towards Southcentral AK.  Snow has begun to fall this morning.  Expect snowfall intensities to pick up throughout the course of the day.  Accumulations of up to up to 14” (.9" H20) can be expected by sunset (7:49pm).  Ridgetop winds will be moderate to strong out of the East averaging 20-30 mph with gusts to 70 mph.  Temperatures at 1,000’ will be in the high 20s to low 30s F.

Snow, which will be heavy at times, will continue overnight and should taper off by Tuesday evening.  Another Low pressure system coming from the Southwest will move into the area on Wednesday, bringing another round of snow.  An active weather pattern will continue through the week as a series of Lows track through the area.

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: Dec 08, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedRain and snow have fallen in Turnagain Pass this week, but not enough to open for snowmachining. Continue to check back to this site for updates.
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail is expected to open to snowmachine use during the 2017/18 winter season.
Snug Harbor: Closed
South Fork Snow River Corridor: Closed
Summit Lake: Closed

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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.


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
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