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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Monday, April 8th 2013
Created: Apr 8th 6:24 am
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.
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Special Announcement

Are you going to Arctic Man this year?  Join Alaska Mining and Diving Supply, the Friends Group and CNFAIC Forecaster Graham Predeger for a free "Hoodoo Mountain Snowpack and Avalanche Assessment" field workshop on Wednesday afternoon!  Meet at the AMDS tent at 2PM for a fun and informative afternoon of snowpits and POW as we try to wrap our heads around what the primary avalanche concerns will be for the week!  Contact Graham at graham@chugachavalanche.org for more information.


The Bottom Line

With 6-10" of new snow on tap today the avalanche danger will rise to MODERATE at all elevations and aspects for storm snow avalanches. These include: wind slab, storm slab and loose snow avalanches. Wind slabs will be the most concerning as they could build to a foot or more in thickness and become quite unmanageable. The most likely place to find one will be above treeline on south through west facing slopes. Otherwise, sluffs and shallow storm slabs within the new snow will be possible to trigger.

The danger will rise to CONSIDERABLE in any area receiving more than 10" of new snow over the course of the day.


Primary Concern

It looks as though winter is back. We have a cold storm moving in this morning that will bring another round of snow all the way down to sea level. Snowfall is just getting going now and is expected to drop ~6" on the Pass during the day with possibly up to 10" in favored locations. Winds associated are not too exciting - light from the east with moderate gusts. That said, new snow with some wind will spice up the avalanche conditions. Snow amounts are modest however, so most of the avalanche activity should be low volume - the exception will be areas the wind is depositing snow into deeper drifts and slabs.

There are three main questions to keep in mind if heading out today:
1- How much snow is accumulating in the area you are traveling? The more snow, the bigger the avalanche.
2- Is the wind blowing and loading slopes? Only 6" of new snow with moderate wind can build sensitive wind slabs over a foot deep (see yesterday's activity below). These could quickly through you down a slope and into an unmanageable situation.
3- How well is the new snow bonding with the variety of underlying surfaces? Slick crusts on southerly aspects will have a hard time holding snow. Northerly aspects have a mix of soft snow, wind affected surfaces and potentially buried surface hoar. I'm expecting bonding on northerlies to be poor in some areas and fairly good in others.

Other than wind slabs mentioned above, we can expect loose snow avalanches in steep terrain to release both naturally or by a person. Also, shallow storm slab avalanches on slopes greater than 35 degrees are possible due to warming temperatures during snowfall.

 


Yesterday's avalanche activity:
Folks were able to find and trigger fresh wind slabs 6-12" deep yesterday on upper elevation northerly slopes. This seemed to be confined to the southern end of the Pass where 4-8" of low density snow fell Saturday evening (only 2-4" fell on the northern side of the Pass). Southerly winds blew during the snowfall and then kicked up again mid-day yesterday continuing to load northerly slopes. We saw a few natural loose snow avalanches in the Lynx Creek area as well - see Fitz's video HERE.

 


Mountain Weather

During the past 24 hours we have seen partly cloudy skies with a trace of snowfall. Ridgetop temperatures reached 20F yesterday before dropping to the single digits overnight. Winds were mainly out of the east averaging 8mph with gusts up to 25mph.

Today we have another, and more developed, system moving in from the Gulf. Turnagain Pass will likely see snow amounts similar to Anchorage (this is a good set up for Anchorage). We should see around 6-10" through the day with warming temperatures. Ridgetop winds are expected to be light from the east with gusts to 25mph. Temperatures should rise to the upper-teens on the ridgetops and to the upper 20's at 1,000' before they cool off again as the flow switches to the north tonight.

Tuesday, colder air moves in from the northwest as the low pressure wraps around southcentral. This could give us several more inches of light snow - and if things set up right, possibly more. Stay tuned.

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I will issue the next advisory tomorrow morning, April 9th.

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: Nov 18, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedOnly a few inches of snow sits at the motorized lot, not enough to open for snowmachining at this time. Updated Nov. 18, 2017
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

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
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