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Tue, January 7th, 2014 - 7:00AM
Wed, January 8th, 2014 - 7:00AM
Wendy Wagner
Avalanche risk The Bottom Line

A CONSIDERABLE avalanche danger exists above treeline for triggering a large slab avalanche 2-3′ deep. Areas of most concern are steep slopes over 35 degrees on all aspects, especially those with prior wind loading. Below treeline the danger is MODERATE for triggering a slab avalanche ~2′ deep. These avalanches are breaking in weak snow near the base of the snowpack.

Conservative terrain selection is the key for a safe day in the backcountry. Safe places to recreate are slopes 30 degrees or less without steeper terrain above or connected to you.

Special Announcements

For anyone who has taken an Avalanche Level 2 course and interested in a refresher check out the Alaska Avalanche School’s €œLevel 2 refresher/Observer Workshop €. The course will be a lot of fun and taught by CNFAIC’s Wendy Wagner and AAS’s Eeva Latosuo.

Tue, January 7th, 2014
Above 2,500'
3 - Considerable
Avalanche risk
2 - Moderate
Avalanche risk
Below Treeline
Below 1,000'
2 - Moderate
Avalanche risk
0 - No Rating
1 - Low
2 - Moderate
3 - Considerable
4 - High
5 - Extreme
Avalanche risk Avalanche risk Avalanche risk Avalanche risk Avalanche risk
Travel Advice Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential. Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain.
Likelihood of Avalanches Natural and human-triggered avalanches unlikely. Natural avalanches unlikely; human-triggered avalanches possible. Natural avalanches possible; human-triggered avalanches likely. Natural avalanches likely; human-triggered avalanches very likely. Natural and human-triggered avalanches certain.
Avalanche Size and Distribution Small avalanches in isolated areas or extreme terrain. Small avalanches in specific areas; or large avalanches in isolated areas. Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. Large avalanches in many areas; or very large avalanches in specific areas. Very large avalanches in many areas.
Avalanche Problem 1
  • Persistent Slabs
    Persistent Slabs
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
More info at Avalanche.org

There was no new avalanche activity reported yesterday. Though once again, few people are venturing into avalanche terrain, including myself. We did get some additional photos sent in of the natural cycle that occurred two days ago (see photo below as well as the link). These avalanches were breaking in the weak snow near the ground and taking the majority of the snowpack with them. Triggering a large slab that sits on the brink is the essence of our primary concern.

Without much change in the weather, it will take a person, group of people or a snowmachine to trigger one of these avalanches. After this last storm the slab is becoming thicker, up to 3’ in places. This can make it harder for your weight to impact the weak layer at the base of the pack and trigger a slide – but the consequences are high.

Below is South facing Lipps Ridge on Turnagain Pass. Avalanche occurred naturally late on 1/4 or early 1/5 (SSW, 3,400’)


A few words on snowpack assessment:
Information has been limited since the end of the weekend’s storm. With little visibility and very few people testing the steeper slopes our main clues for evaluating the snowpack continue to be snow pit data and collapsing.

Snow pit data: What we are finding is a slab between 2 and 3 feet thick composed of all the December and January snow (4.8” water equivalent at 1880ft). Under this is the well documented weak faceted snow above and below the December drizzle crust. Stability tests are showing that it’s getting harder to collapse the weak layer(s), but once failure occurs all bets are off and large dangerous avalanches are likely if the slope is steep enough. 

Collapsing: Several people, including our staff, continue to report collapsing while traveling. This means a person can trigger a failure in the weak faceted snow and subsequently an avalanche. What this tells me is that even though the pit data says it should be hard to trigger a slide, maybe it’s not that hard after all. These obvious signs of instability should always trump pit results.

Below 1,500’ a series of crusts and wet snow make up the snowpack and triggering an avalanche is unlikely.

Tue, January 7th, 2014

Yesterday morning a small system moving through added 1-2 € of snow to the upper elevations on the Pass and .1 € of rain below 1,500′. Alyeska, on the other hand, was favored and reported 6 € on the upper mountain with rain at the base. Winds during the past 24-hours have decreased from the 20mph range to the 5-10mph range from the East and temperatures have remained in the 20’s on the ridgelines and low 30’s at 1,000′.

Today we should see mostly cloudy skies and warm Southeasterly flow with no precipitation. Temperatures look to remain in the mid 20’s above treeline and low 30’s below treeline. Ridgetop winds will be light from the Southeast in the 10mph range.

Tonight into tomorrow the warm conditions remain with a chance for 1-2 € of snow and rain below 500′. The next good shot of precip is difficult to tell as the weather models are having a hard time with the extended outlook.

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Date Region Location
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11/26/23 Turnagain Observation: Road report: Slide with dirt on Repeat offender
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11/25/23 Turnagain Observation: Tincan trees
11/21/23 Observation: Spokane Creek
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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.