Thursday, April 2nd 2015 5:24 am by Graham Predeger
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
The avalanche danger is MODERATE today above treeline. Human triggered avalanches 2-3’ deep are possible in isolated areas, particularly North facing terrain. This looks to be the first day in a week without some measurable precipitation so it’ll be important to let the snowpack continue to adjust to this recent load. Keep your terrain choices conservative today and as always, practice safe travel protocol when moving through the mountains.
Other concerns today include the impending cornice hazard and wet loose avalanches; both of which may be influenced by a warm Spring day on tap.
Below 2500’, the danger is LOW though potential exists for an avalanche or cornice initiated in the alpine to run into this elevation band.
|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.|
Many observations over the last week have pointed toward a strengthening snowpack in the core advisory area. The exception to this appears to be North aspects above treeline as we’ve had reports of large avalanches in these areas over the last two days; most recently yesterday a skier triggered an avalanche and went for a 1,000’ ride on the north side of Magnum. Let's not forget that we have seen 3-5 feet of snow in the alpine (consolidated to 2-3 feet) over the last week that fell on a myriad of different surfaces. Upper elevation north aspects are notorious for harboring weaker snow longer, which is exactly where surface conditions are best, but also where unstable snow is being found. Recognize that if an avalanche is initiated, it will likely be big and encompass at least the last week’s storm (2-3’) with the potential to step down deeper.
As days grow longer (gaining 5 min 44sec today!) and sunnier, the temptation to ski bigger lines and push further out from the road and into periphery areas is strong. With this, safe travel protocols become increasingly important. Expose only one person at a time on a slope and utilize good communication and true islands of safety.
Defying gravity seems an accurate term for some cornices right now. Given the last seven days of sticky snow and moderate ridgetop winds many of these have grown to full-curl. Some have failed (Pyramid West face and Todd’s run) but many have only grown closer to the breaking point. This is a much simpler problem than the aforementioned persistent slab because we can see cornices; and what we can see, we can avoid. Simply minimize time spent underneath and give these backcountry bombs an extra wide berth when travelling on ridgelines.
Hippy bowl ridge and large, curling cornice.
Daytime heating and light winds could be concern for wet loose avalanches on steep south and west facing slopes today. Generally slow moving, these are a different beast than a slab avalanche. Wet loose activity is generally of concern if the potential exists to push you off your skis and into a terrain trap.
Yesterday morning started out with an intense band of snow moving through Turnagain pass depositing a quick 2-4” at the road. Temperatures warmed throughout the day and intermittent periods of sun through broken clouds proved enough to melt that little bit of accumulation by 5pm. On ridgetops, temps were in the mid 20’s, winds light to moderate from the northeast and intermittent snow showers added up to 3-5” (above 2,000’) on the northern side of Turnagain pass.
Today looks to be the start of a clearing trend that will last through the weekend with no precipitation forecasted. Expect temps to be warm today (mid-30’s at 3,000’) and wind shifting to the north in the 10-20mph range as an outflow (off shore winds) regime sets up. Slightly cooler air will filter in tomorrow and through the weekend under clear skies.
PRECIPITATION 24-hour data (6am - 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880')||32||2||.2||59|
|Summit Lake (1400')||35||0||.04||10|
|Alyeska Mid (1700')||33||2||.15||36|
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|
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