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Archives
ARCHIVED - Forecasts expire after 24 hours.
Issued
Mon, November 12th, 2012 - 7:00AM
Expires
Tue, November 13th, 2012 - 7:00AM
Forecaster
Wendy Wagner
Avalanche risk The Bottom Line

Due to early season conditions, for both the snowpack and our operations, we will be issuing intermittent snow and avalanche updates until November 17th, as conditions dictate.

BOTTOM LINE
Avalanche conditions in the Turnagain Pass area have stalled out during the past week. Areas below treeline and lower angle slopes are where people have been recreating and these areas have remained intact. The most likely place to trigger an avalanche continues to be the upper elevation steeper slopes. These areas are believed to be hanging in the balance, due to our poor snowpack structure, and need either a person or a decent storm to get them to slide.

ANNOUNCEMENTS
Don’t forget to check the photos/observations page for early season information. Also, the calendar page is filling up with free awareness classes and other avalanche education courses offered in our area.

SNOWPACK and AVALANCHE DISCUSSION  
With only a few inches of new snow falling over the weekend with rain below 1000′ the avalanche conditions are in somewhat of a stale mate. The surface (and riding) conditions on the other hand have definitely changed. A thin crust caps the snowpack from ~2,000′ and becomes thicker below. Above treeline dry snow still exists with varying degrees of wind slab and unsupportable loose snow. Total snow depth varies from one to three feet.

The most concerning areas for triggering an avalanche remain untouched. These are the upper elevation steeper slopes. Many of these areas are also still riddled with rocks, making them fairly uninviting from that perspective as well. Exposed areas got their fair share of wind over the weekend forming stiff wind slabs. Traveling in this type of terrain yesterday we had several collapses and cracking in nearly all of the wind loaded areas we stepped on. The layer collapsing is the weak snow from October. Below is a pit dug in one of these upper elevation wind loaded locations.

These pit results say the snowpack has the right ingredients for a slab avalanche but in order to slide there needs to be some kind of rapid load (i.e., a person in the right place or a good shot of snow).

Looking forward to the next significant storm, triggering an avalanche that breaks into the Oct facets is a real possibility (the system rolling through this week does not look to have enough umph). These slides could propagate in areas that are not expected. Remote triggers (for example, triggering an avalanche on top of you from below) will be possible and conservative route finding will be the ticket until this faceted layer gets enough load to either flush out with widespread avalanche activity and/or has time to adjust to the load.

Mon, November 12th, 2012
Alpine
Above 2,500'
0 - No Rating
Avalanche risk
Treeline
1,000'-2,500'
0 - No Rating
Avalanche risk
Below Treeline
Below 1,000'
0 - No Rating
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

This week we have seen a lull in both the weather and avalanche activity, but with new snow and wind on the way for the weekend we can expect that to change. Storm snow instabilities within the new snow, in the form of sluffs and storm slabs, will be likely if the forecasted 10-14″ of snow verifies. These problems should settle out rather quickly, in a day, or at most 2 days.

However, the bigger story, and most concerning, is the new snow load reactivating the old October facets (see image below). It only took 6-10″ of new snow last weekend to create a very touchy slab avalanche problem. With this storm, the facets are not quite as loose as they were a week ago now that they have been buried for 5-6 days. Yet, they are still there and reactive and have the potential to produce larger avalanches this time around. If we get enough snow and wind to get them going that is. The one thing this system does have that the last one didn’t are much stronger winds. These will produce larger wind slabs that form both near (like last weekend) and well off the ridgelines (unlike last weekend).


Snowpack before the Fri-Sun (11/9-11/11) storm sets in. Main concern is faceted layer. Existing surface is generally composed of soft decomposing fragment from last storm.

Any avalanche triggered within the old Oct snow will be around 1-3′ deep and could propagate in areas that are not expected. Remote triggers (for example, triggering an avalanche on top of you from below) are possible. Hence, very conservative route finding is the ticket until this faceted layer gets enough load to either flush out with widespread avalanche activity and/or has time to adjust to the load.


Above cracking is a red light to stick to lower angle slopes, 30 degrees or under (including what is above you).

Weather
Mon, November 12th, 2012

Last weekends storm added a mere 2-4″ of snow above treeline and wet snow and rain below. This coming Tuesday night through Thursday another system is headed our way that is taking a similar path. However, this systems looks to be a bit cooler. Right now the models are showing snow totals to be minimal, a few inches in the Turnagain area with possibly up to 8″ if we get lucky.

Stay tuned at our weather page.

Observations
Recent Observations for Turnagain Pass
Date Region Location Observer
10/27/24 Turnagain Observation: Tincan Michael Kerst
10/21/24 Turnagain Observation: Turnagain Pass Road Observation Trevor Clayton
10/19/24 Turnagain Observation: Tincan – Below Todds Run Andy Moderow
10/18/24 Turnagain Observation: Taylor Pass Eli Neuffer
10/15/24 Turnagain Observation: Tincan Common John Sykes Forecaster
10/14/24 Turnagain Avalanche: Tincan CNFAC Staff
05/13/24 Turnagain Observation: Eddie’s, Sunburst, Seattle, Cornbiscuit, Pete’s South H Thamm
05/13/24 Turnagain Observation: Turnagain Pass non-motorized side Amy Holman
05/12/24 Turnagain Observation: Warm up Bowl Tony Naciuk
05/07/24 Turnagain Observation: Turnagain Pass Wet Slabs A S
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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.
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