Turnagain Pass RSS

Archives
ARCHIVED - Forecasts expire after 24 hours.
Issued
Sun, December 6th, 2015 - 7:00AM
Expires
Mon, December 7th, 2015 - 7:00AM
Forecaster
Heather Thamm
Avalanche risk The Bottom Line

A generally LOW avalanche danger exists across all elevations bands for the Turnagain Pass zone. In steep terrain near rocks where the snowpack is thinner triggering a slab 1-3′ thick is unlikely, but could have high consequences. Ease onto steep slopes one at a time and be mindful of people below you and on adjacent slopes.

*If venturing into the ‘periphery’ forecast zones, such as Girdwood Valley, Silvertip and Summit Lake areas, more caution is advised due to limited information about the snowpack in these areas.

Sun, December 6th, 2015
Alpine
Above 2,500'
1 - Low
Avalanche risk
Treeline
1,000'-2,500'
1 - Low
Avalanche risk
Below Treeline
Below 1,000'
1 - Low
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

Yesterday Turnagain Pass saw many ‘slope testers’ (skiers and riders) pushing into steeper terrain and no red flags (recent avalanches, whumphing or shooting cracks) have been reported in nearly a week. Since the Thanksgiving rain event ended over a week ago a wet snowpack has frozen leaving a stable stout crust below 2500’. In the Alpine snow depths vary from 1-5’ thick with a generally thinner snowpack on Northern and Eastern slopes. In areas where the snowpack is thinner a slab 1-3’ thick sits on top of pockets of weaker snow near the ground. Because we lack x-ray vision it is unclear how widespread this basal faceted snow is across any given slope. This poor structure has shown some propagation potential in test pits this week, making it difficult to ignore. Triggering such a problem is an outlier, yet is possible in thinner areas near rocks. Caution is warranted if planning to push into steep complex terrain above 3000′. 

Snow depths in the higher elvations of Pastoral averaged between 3-5′ thick, but a poor structure can still be found. Click Here to view yesterday’s observation.

Additional Concern
  • Normal Caution
    Normal Caution
Normal Caution
Normal Caution means triggering an avalanche is unlikely but not impossible.
More info at Avalanche.org

Calm winds this week have left 8” of low-density surface snow to settle out making skiing and riding conditions quite good. Small natural point release ‘sluffs’ were observed yesterday on steep slopes in the Alpine. This is a minor concern, not enough volume to bury a person, but has the potential to knock you off your feet. 

The snow quality right now is arguably the best it’s been in over a year so no doubt the usual zones in Turnagain will be crowded.  Keep other adjacent groups in mind as you are moving through the mountains today and maintain good backcountry etiquette.  Wear and know how to use your rescue gear, expose one person at a time on a slope, discuss potential consequences if a slope does slide and don’t ski on top of other parties.

Northern aspect of Magnum ridge, where small natural point releases were observed yesterday.

 

Weather
Sun, December 6th, 2015

Yesterday above 1000′ skies were clear, temperatures were around 20F and winds were calm. In the surrounding valleys a dense fog left behind a trace of new snow.

Today a similar pattern is expected. Temperatures should remain in the low 20F and gradually warmer in the Alpine as a result of a slight inversion. Ridgetop winds are expected to be light from the Northeast, with mostly clear skies.

The first hint of a shift in the weather is Tuesday for possible snow.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 20F   trace   0.05   24  
Summit Lake (1400′) 15F   0    0 11  
Alyeska Mid (1700′) 20F   trace    0.05 20

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 20F   NE   3   7  
Seattle Ridge (2400′) 19F   n/a   n/a   n/a  
Observations
Recent Observations for Turnagain Pass
Date Region Location
10/27/24 Turnagain Observation: Tincan
10/21/24 Turnagain Observation: Turnagain Pass Road Observation
10/19/24 Turnagain Observation: Tincan – Below Todds Run
10/18/24 Turnagain Observation: Taylor Pass
10/15/24 Turnagain Observation: Tincan Common
10/14/24 Turnagain Avalanche: Tincan
05/13/24 Turnagain Observation: Eddie’s, Sunburst, Seattle, Cornbiscuit, Pete’s South
05/13/24 Turnagain Observation: Turnagain Pass non-motorized side
05/12/24 Turnagain Observation: Warm up Bowl
05/07/24 Turnagain Observation: Turnagain Pass Wet Slabs
Riding Areas

The riding areas page has moved. Please click here & update your bookmarks.


Subscribe to Turnagain Pass
Avalanche Forecast by Email

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.