Turnagain Pass RSS

Archives
ARCHIVED - Forecasts expire after 24 hours.
Issued
Thu, March 22nd, 2012 - 7:00AM
Expires
Fri, March 23rd, 2012 - 7:00AM
Forecaster
Graham Predeger
Avalanche risk The Bottom Line

Good morning. This is Graham Predeger with the Chugach National Forest Avalanche Information Center on Thursday, March 22nd at 7am. This will serve as 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).

BOTTOM LINE

There continues to be a MODERATE avalanche danger for the core advisory area today. Buried sun crusts/facet combinations and buried surface hoar have the potential to act as the weak layer in which an avalanche can initiate. Additionally, pay close attention to and avoid slopes on the south end of the compass late in the day as intense solar radiation can easily tip the balance between stable and unstable snow this time of year.

AVALANCHE DISCUSSION

Several persistent weak layers have been buried over the last couple of weeks contributing to a poor structure in our upper snowpack. Test results over the last several days are hinting that our first buried surface hoar layer (24-30″ down) is gaining in strength but when disturbed, this layer is showing the potential to propagate with clean quality 1 shears. Additional persistent weak layers in our upper snowpack include buried sun crusts/ facet combinations and a more recent layer of surface hoar buried during Monday’s storm.

Concern #1 Buried Sun Crusts

These will be found on slopes with a southerly-tilt today (there are several in the top three feet of our snowpack). Faceting snow above and below these crusts proves an excellent weak layer for an avalanche to run on. There have been several skier-triggered avalanches in the last week where these crust/ facet combinations have been the culprit.

Concern #2 Loose sluff and wet slabs

North aspects will be holding dry, quality powder throughout the day. Sluffing was commonplace yesterday in steeper terrain (> 38 degrees) with loose snow traveling fast and far. South aspects however are a different story. The surface consists of a breakable crust with a few inches of powder on top. This will be some of the worst skiing and snowmachining today and the most dangerous as they continue to heat up throughout the day. It is imperative that travelers avoid these south-facing slopes late in the day, as this is when the slopes are ripe to avalanche.

Pay particularly close attention to clues that south-facing slopes are undergoing rapid warming. This may include roller-balls, point releases or sinking (boot penetration) when you step off your snowmachine or skis.

Concern #3 Buried surface hoar

It will take finding the sweet spot or a large load such as a snowmachine or cornice drop to trigger the deepest (approx. 24-30″ down) buried surface hoar layer today. If this layer is affected, it will likely propagate and have the potential to become a large and destructive avalanche. The more recent buried surface hoar layer (6-8″ down) doesn’t have a cohesive slab on top of it yet. Though buried intact, it won’t be a big issue for slab avalanches until we get anCNFAIC Staff significant wind or snow event to create that slab.

MOUNTAIN WEATHER

This will be the third day since the core advisory area has seen any significant snowfall or wind.

Today looks to be starting out significantly warmer than yesterday with valley temps at 18 degrees this morning (single digits 24hrs ago). We can expect anCNFAIC Staff day of stable weather today with partly sunny skies, light wind and temperatures to reach into the lower 30’s.

CNFAIC Weather Page and the NWS forecast

Chris will issue the next advisory Friday morning. If you get out in the backcountry we want to know what you are seeing. Please send us your observations using the button at the top of this page or give us a call at 754-2369. Thanks and have a great day.

Thu, March 22nd, 2012
Alpine
Above 2,500'
2 - Moderate
Avalanche risk
Treeline
1,000'-2,500'
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.
Observations
Recent Observations for Turnagain Pass
Date Region Location
02/25/24 Turnagain Observation: Kickstep NE Bowl
02/24/24 Turnagain Observation: TinCan Backdoor/ Center Ridge
02/22/24 Turnagain Avalanche: Lynx Creek
02/22/24 Turnagain Observation: Turnagain, Seattle, Mt Ascension
02/21/24 Turnagain Observation: Tincan Trees
02/21/24 Turnagain Observation: Sunburst
02/20/24 Turnagain Avalanche: Tincan
02/20/24 Turnagain Observation: Seward Highway across from Johnson Pass TH
02/19/24 Turnagain Avalanche: Base of Seattle Ridge
02/18/24 Turnagain Observation: Lynx creek
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.