Avalanche Advisory

Turnagain Area Avalanche Advisory Tuesday, March 3rd 2015 6:17 am by John Fitzgerald ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.

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The avalanche danger is MODERATE in the Alpine, where slabs 1-2’ in depth could be triggered in steep terrain.  Triggering these slabs is on the low end of the scale but consequences remain high enough to warrant careful snowpack and terrain assessment.

The danger is LOW at Treeline and below where triggering an avalanche is unlikely.

Despite it being early March, early season conditions exist on the approaches.  Ice, alder stumps and rocks are hazards to avoid when traveling to and from the treeline elevations today.

Show the Complete North American Avalanche Danger Scale

North American Public Avalanche Danger Scale Avalanche danger is determined by the likelihood, size and distribution of avalanches. Danger Level Travel Advice Likelihood of Avalanches Avalanche Size and Distribution 5 Extreme Avoid all avalanche terrain. Natural and human- triggered avalanches certain. Large to very large avalanches in many areas. 4 High Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. Natural avalanches likely; human- triggered avalanches very likely. Large avalanches in many areas; or very large avalanches in specific areas. 3 Considerable Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential. Natural avalanches possible; human- triggered avalanches likely. Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. 2 Moderate Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Natural avalanches unlikely; human- triggered avalanches possible. Small avalanches in specific areas; or large avalanches in isolated areas. 1 Low Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Natural and human- triggered avalanches unlikely. Small avalanches in isolated areas or extreme terrain. Safe backcountry travel requires training and experience. You control your own risk by choosing where, when and how you travel.

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.

0 NO RATING Below Treeline / Below 1,000'

Join us tonight for a FREE avalanche awareness talk and discussion on the state of the snowpack at REI in Anchorage from 6-7:30pm!!  Cost is zero dollars.

Avalanche Problem 1

Weak snow that has been buried for 3 weeks continues to lurk 1-2 feet below the surface.  This layer has gained significant strength in that time.  Bonding between the “late January” facets and overlying slabs has improved to the point where it has become difficult to trigger an avalanche on this layer.  Some intermediate weak layers can be found in isolated locations and are buried about 1 foot deep.  Slabs resting on these layers are also generally difficult to trigger.   Tests have been showing propagation potential on the decline, but it is still possible for an avalanche, if triggered, to propagate across portions of slopes.  

Despite these improving trends it is still important to treat steep and complex terrain with suspicion in the Alpine.  Today it will be important to follow good travel protocol.  Assess the terrain you are on and minimize your exposure accordingly.  Avoid trigger points on terrain over 35 degrees, travel one at a time on suspect slopes, use islands of safety and communicate your decisions and plans within your group.

Avalanche Problem 2

Ridgetop winds have been in the 20-30 mph range since yesterday morning.  Very shallow stiff slabs may be encountered today on steep (40 degrees and over) leeward slopes.  These slabs will be small, around 4-6” deep and exist in small pockets.  While the volume of any wind slabs triggered will be low, it will be important to avoid them when travelling above terrain traps such as cliffs, gullies and trees.

The past 24 hours saw mild temps with moderate ridegtop winds.  Skies were mostly cloudy and less than a trace of new snow fell in the upper elevations.

Today expect more of the same.  Winds will be out of the East at 15-20 mph.  Very light snow under mostly cloudy skies will fall with a max of 2” of accumulation.  Rain/snow line will be around 1,000’.  Temperatures at 1,000’ will be in the low to mid 30s F.

The extended outlook is showing a continuation of showery precipitation through the week, as a series of weak lows move through the area.

PRECIPITATION 24-hour data (6am - 6am)

RIDGETOP 24-hour data (6am - 6am)

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 )

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