Avalanche Advisory

Turnagain Area Avalanche Advisory Saturday, January 24th 2015 6:28 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 LOW in the Alpine and Treeline elevations today.  Triggering avalanches are unlikely.  

At and below treeline “early” season conditions exist.  Meager snow coverage between 1,000-2,500’ will make for challenging travel.  Rocks, stumps, and slick surfaces are legitimate hazards to manage in the mid 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.

1 Low Alpine / Above 2,500'

Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

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'

Avalanche Problem 1

It has been over a week since the last significant loading event.  In that time temperatures have been mild and winds have been mostly light.  This has allowed instabilities that did exist in the upper portions of the snowpack to diminish.  Because of this it will be very difficult to trigger an avalanche today.

Keep in mind that LOW danger does not mean NO danger.  It is impossible to eliminate all risk if you are spending time in avalanche terrain in the winter.  Outlier issues today could come in the form of:

Wind Slabs
Moderate winds yesterday morning created very shallow pockets of wind slab above 2,500’.  These slabs are in the 4-6” range, low in volume and could grow slightly in areas receiving snow today.  If venturing into very steep upper elevation terrain be on the lookout for these small pockets as they could push you around or knock you off your feet.  

Glide Avalanches
We continue to track and monitor glide cracks throughout the forecast area.  Cracks exist on all aspects and are generally found between 2,000’ and 3,000’.  The solution to this problem is simple: stay away from glide cracks.  They are unpredictable and could release at any time.

Eddie's has many glide cracks.  Many on the South side have released.  Note the large crack on the headwall which has not released.  Photo: Fitzgerald

If you are traveling in steep terrain today it is important to follow good travel protocol:
-One at a time on suspect slopes
-Use islands of safety for spotting and regrouping
-Communicate decisions and plans effectively
-Be aware of other groups above and below

Don’t get lazy in times of LOW danger.  Developing good habits will serve you well when the danger is higher than it is today.

Over the past 24 hours the mountains around Eastern Turnagain Arm have picked up a trace to 2” of new snow.  Winds have been light with ridgetops averaging in the 5-10 mph range out of a variety of directions.  Temperatures have been on a steady downward trend with ridgetop stations reporting in the teens F this morning.

Today expect lingering snow showers to give way to clearing skies and a drop in temps.  Some areas could receive an additional 2” of snow.  Winds will be light out of the North in the 5 mph range.

A ridge of high pressure will begin building over the area later today and persist into the early part of next week.  Cold air will remain in place for the region with lows below zero F and highs in the single digits to teens F.

*Seattle ridge wind data is 6 am-11pm.  The wind sensor is rimed.

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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