Wednesday, November 30th 2016 6:07 am by Heather Thamm
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
The avalanche danger will start out as MODERATE in the alpine, and could easily increase to CONSIDERABLE throughout the day depending on how much snow falls. Triggering a slab 1 - 3 feet thick will become likely if we receive the higher snowfall amount, up to 15 inches. Cautious route choices and conservative decision making will be essential to adapt to today's changing weather.
Expect a MODERATE avalanche danger today at treeline where triggering a storm slab up to 1' thick is possible depending on snowfall amounts.
|Show the Complete North American Avalanche Danger Scale|
|Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.|
|Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.|
A low pressure system in the Eastern Gulf will combine with cool Northern arctic air over Southcentral Alaska today. There is a “fair amount of uncertainty on snow amounts” impacting Turnagain Pass, but expect snow totals to be anywhere between 5-15 inches. Moderate Easterly winds (10-25mph) are also expected which could easily increase the avalanche danger throughout the day especially if snowfall intensifies. It will be important to adapt your travel plans to changing weather conditions and be on the lookout for any signs of instability; shooting cracks, whumphing sounds, or recent avalanches.
Don’t forget what this snow is falling on. A reactive layer of buried surface hoar from Nov.16 lies below 1-2 feet of old snow. This widespread layer exists on all aspects and has been the culprit in dozens human triggered avalanches over the last two weeks including the most recent on Sunday Nov.27 in Seattle Creek area. Today’s weather has the potential to re-load this weak layer increasing the likelihood for human triggered avalanches. Slab depths could be as thick at 1.5-3 feet thick depending on snowfall amounts. Cautious route choices and conservative decision making will be essential today.
Buried surface hoar is still a very visible layer and continues to be reactive in tests pits. Photo taken at 3200' on a SW aspect of Tincan on 11/27 by Aleph Johnston-Bloom
Today’s new snow will be falling on weak old snow; snow that has been 'faceting' due to cold temperatures this week. The combination of wind and the possibility of higher snowfall totals (up to 15") could produce storm slabs 1’ thick both in the alpine and at treeline.
Watch for glide cracks and remember to limit time under these, there have been a handful that released last week. *Several cracks have been opening in popular terrain like Tincan’s Common bowl and the SW face of Sunburst.
Yesterday was cold and clear. Temperatures were in the single digits and light to moderate ridgetop winds made for a windchill of -5F to -20F below zero. Winds varied from North to Southwest and no new precipitation was recorded.
Today 5-15 inches of snowfall (up to 0.5 inches of water) is expected today in the upper elevations of Turnagain Pass. Temperatures will start out cold and warm up in to the 20F’s throughout the day. Easterly ridgetop winds are expected to be moderate (10-25mph.)
Tonight and tomorrow more snow is expected throughout the region. Its hard to say how much will impact our area, but temperatures are staying cool enough that it should all fall as snow.
***We are happy to report as of 3pm yesterday Sunburst Weather Station is back online!
PRECIPITATION 24-hour data (6am - 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880')||6||0||0||17|
|Summit Lake (1400')||1||0||0||3|
|Alyeska Mid (1700')||8||0||0||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: Apr 22, 2018 )
|AREA||STATUS||WEATHER AND RIDING CONDITIONS|
|Johnson Pass:||Closed||Closed as of April 20th|
|Placer River:||Closed||Closed as of April 17th|
|Skookum Drainage:||Closed||Closed as of April 1st.|
|Twentymile:||Closed||Closed as of April 13th|
|Lost Lake Trail:||Closed||Closed as of April 13th|
|Primrose Trail:||Closed||Closed as of April 13th|
|Resurrection Pass Trail:||Closed||Closed as of April 20th|
|South Fork Snow River Corridor:||Closed||Closed as of April 13th|
|Summit Lake:||Closed||Closed as of April 20th|
SNOW AND AVALANCHE HOTLINE (907) 754-2369
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