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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Tuesday, March 18th 2014
Created: Mar 18th 6:27 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.
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.
 Show the Complete North American Avalanche Danger Scale
The Bottom Line

There is a MODERATE avalanche danger on all aspects and elevations above 2,000'. The possibility remains for a person, group of people or snowmachine to trigger a large, 3-5+' deep, and destructive slab avalanche. Areas of most concern are steep slopes that have seen prior wind loading. Areas of most concern for triggering are shallow zones, commonly near rocks and the tops of rollovers.

Below 2,000' the danger is generally LOW. At these lower elevations triggering an avalanche will be unlikely. 

Note: Not all MODERATE dangers are created equal. The 'Avalanche Problem' we have today is Deep Slab and with that a MODERATE danger means the chances are you won't trigger an avalanche, but if you do it is likely to be unsurvivable. This is the 'low likelihood - high consequence' conundrum and something that deserves our respect.


Primary Concern

Once again, the main concern boils down to how our snowpack is adjusting to last week's 3-5' of heavy storm snow. The good news is, all signs for the past couple days have pointed to the new snow/old snow interface (3-5' slab over weak preexisting snow) gaining strength. Though this is great news, it's not something to completely hang a hat on, yet. It was only 3 days ago now that we had good enough visibility for folks to test the slopes and come away with a handful of human triggered large - and dangerous - avalanches. Also, we are still only 4 days out from the end of the storm itself. A bit more time to really let the snowpack prove innocent is warranted.

Though the likelihood of triggering a deep slab continues to decrease, the size of a potential slide remains large. Due to the high consequences, conservative terrain choices remain the best way to manage the problem. This means avoiding steep slopes, especially those with prior wind loading, and likely trigger points.  Likely trigger points include shallow spots in the snowpack and steep rollovers. For those with a higher risk tolerance, safe travel practices are key in avalanche terrain - this includes only exposing one person at time and keeping a close eye on your partners.

*Areas that have a higher likelihood are places that did not receive as much snowfall from last week's storm and have a shallower overall snowpack. For example the central Kenai - Palmer Creek area, Silvertip region and Summit Lake zones.


Secondary Concern

By the look of the satellite imagery this morning, the sun may shine more than expected today. Also, the winds are slated to be calm to very light. These factors combined can create significant warming at the snow surface. If this is the case today, watch for damp to wet loose avalanches on southerly aspects. These would likely just entrain the light 3-5" of snow from Sunday.


Mountain Weather

It was one of those overcast and low visibility days yesterday. Light snow showers were off and on but only added a trace of snow. Temperatures during the past 24-hours have averaged in the upper teens on the ridge tops and winds have been light, 5-10mph, from the East.

Today, we may see a few snowflakes before skies begin to clear. Temperatures are expected to climb to the low 30'sF at 1,000' and around 20F on the ridgelines. Winds look to shift to the NW this morning and remain light, around 5mph, before picking up to the 20mph range late tonight.

Mostly clear skies and mild temperatures are on tap for Wednesday and Thursday as high pressure builds over mainland Alaska. This high looks to persist into the weekend. 

 

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: Apr 28, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: ClosedSKOOKUM DRAINAGE CLOSED TO MOTORIZED USE ON APRIL 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: OpenOpen thru May 14th.
Twentymile: Closed
Seward District
Carter Lake: OpenClosed May 1.
Lost Lake Trail: OpenClosed May 1.
Primrose Trail: OpenClosed May 1.
Resurrection Pass Trail: ClosedClosed for 2016/17 winter season. This is a non-motorized season. This alternates every other year and will open again during the 2017/18 winter.
Snug Harbor: OpenClosed May 1.
South Fork Snow River Corridor: OpenClosed May 1.
Summit Lake: OpenClosed May 1.

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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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