Monday, February 9th 2015 6:48 am by John Fitzgerald
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
The avalanche danger is generally LOW on Turnagain Pass. Isolated pockets of slab up to 8” in depth may be encountered on steep leeward slopes in the Alpine. It is in these areas where the danger is MODERATE today.
In the Girdwood Valley the danger is MODERATE in the Alpine, where recently formed wind slabs 6-8" (and up to 1') in depth rest on a layer of weak snow. Avoidance of steep terrain harboring stiff wind loaded snow will be important today.
|Show the Complete North American Avalanche Danger Scale|
|Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.|
|Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.|
The last 3 weeks of clear and cool weather has helped to create very weak snow on the surface throughout the forecast area. A lack of significant loading from precipitation or wind has kept avalanche activity to a minimum. An exception to this was found over the weekend in the Girdwood Valley, where strong Northerly winds on Friday loaded fresh slabs onto this weak snow surface. Turnagain Pass was shielded by the Chugach Range from this outflow wind event.
What this leaves us with is a tale of two different snowpacks.
On Turnagain Pass, the core of the forecast area, you will find very shallow pockets of fresh slab 3-4” deep that have built as a result of light snowfall and moderate winds over the past 24 hours. Wind will help to build slabs as thick as 8” by the end of the day on leeward slopes. These pockets could become deeper if additional snowfall exceeds the forecasted 2-3” snow for today.
In the Girdwood Valley you can expect to encounter stiff wind slabs in the mid to upper elevations that are several days old. These slabs are hard and sitting on very weak snow. These slabs will grow slightly today with average depth in the 6-8" range. It is important to be able to recognize wind loaded features. Wind loaded slopes will feel stiff and sound hollow. Shooting cracks radiating from your skis, board or feet are an obvious indicator of unstable snow.
In areas not affected by wind, expect sluffing to occur easily in steep terrain. New low density snow combined with the older weak snow will be easy to trigger and low in volume. If visibility allows travel into upper elevation steep terrain today, watch any sluff that you trigger and steer away from it.
A frontal boundary pushing up from the south has helped to bring about a change over the past 24 hours. Light amounts of snow have accumulated, with 2” of new snow on Turnagain Pass. Temperatures have seen a pronounced upswing, with ridgetop stations reading in the teens to 20 F range this morning. Winds out of the East have also picked up with Sunburst reporting averages in the teens to 20 mph overnight.
Today expect showery conditions. Snowfall amounts will be light, in the 2” to 3” range. Ridgetop winds will be out of the East at 10 to 15 mph. Temperatures at 1,000’ will be in the mid to high 20s F.
An unsettled pattern will help to bring chances for snow through the coming week. Temperatures will fluctuate and gradually rise as we move through the work week.
PRECIPITATION 24-hour data (6am - 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880')||11||2||.1||33|
|Summit Lake (1400')||7||trace||trace||7|
|Alyeska Mid (1700')||10||2.3||.12||24.5|
RIDGETOP 24-hour data (6am - 6am)
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
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).
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: Jan 13, 2019 )
|AREA||STATUS||WEATHER AND RIDING CONDITIONS|
|Twentymile:||Closed||Closed. Forest Service is monitoring conditions.|
|Lost Lake Trail:||Open||Please stay on trail to avoid resource damage through forested areas.|
|Primrose Trail:||Open||Please stay on trail to avoid resource damage through forested areas.|
|Resurrection Pass Trail:||Closed||Closed for the 2018/19 season. Next season will be open to motorized use.|
|South Fork Snow River Corridor:||Open|
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