Tue, November 11, 2014 Turnagain Pass Avalanche Forecast

Tue, November 11th, 2014

Alpine

Above 2,500'

0 - No Rating

Treeline

1,000'-2,500'

0 - No Rating

Below Treeline

Below 1,000'

0 - No Rating

1 - Low

2 - Moderate

3 - Considerable

4 - High

5 - Extreme


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

Glide Avalanches

Glide Avalanches

Glide Avalanches are the release of the entire snow cover as a result of gliding over the ground. Glide avalanches can be composed of wet, moist, or almost entirely dry snow. They typically occur in very specific paths, where the slope is steep enough and the ground surface is relatively smooth. They are often proceeded by full depth cracks (glide cracks), though the time between the appearance of a crack and an avalanche can vary between seconds and months. Glide avalanches are unlikely to be triggered by a person, are nearly impossible to forecast, and thus pose a hazard that is extremely difficult to manage.

More info at Avalanche.org

Glide avalanches, wet slab and wet loose avalanches continue to plague the backcountry in what we are affectionately calling the “Nuri Cycle”. It was Typhoon Nuri after all that pushed the jet stream South, only to bring back with it warm and moisture-laden air. Beginning Friday 11/7, rain falling on snow combined with warm temperatures destabilized the snowpack and avalanches began to fail at or near the ground. We have had many photos sent in to us – THANK YOU! Below are just a couple examples:

This is the West face of Orca from the old town of Girdwood (11/10).

Almost countless glide cracks and releases on Tincan’s Westerly face. The treed rollovers as well as above treeline slopes are good places to avoid for obvious reasons right now.

*Most of these avalanches are glide avalanches and glides have the tendency to avalanche when the snowpack starts to cool down and freeze – or even when it has been cool for several days. So, when the skies clear and the pack is hardening it DOES NOT mean that glide avalanches are through. This is very important to keep in mind when you venture out on the next clear day!

Avalanche Problem 2

Storm Slabs

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

More info at Avalanche.org

We have very little information for the upper alpine zones (above ~3,500′). There are no weather stations with snow data that high in elevation, but we do know it has been snowing! Hopefully the cracks on the glaciers are beginning to fill in and a base it being set for the year.

If you find yourself in the higher terrain be on the lookout for storm snow avalanches – most likely in the form of wind slabs. Some of these could be quite large as the easterly winds have been averaging in the 20’s and 30’s with gusts to 70mph. Watch for signs of recent avalanches, listen and feel for collapsing or cracking in the snow and feel for snow that is “punchy” (stronger/harder snow over weaker/softer snow). These are all signs of instability.

Weather

Tue, November 11th, 2014

As the remnants of Nuri slowly exit we should see another round of rain tomorrow and clearing skies by Thursday or Friday. The temperatures look to remain unseasonably warm however. See below for a look at just how early November is shaping up. Notice the green line, which is snow depth, that has been decreasing as the rain snow line increases. The scale for snow depth is cut off but, as of today we are at 13″ total snow depth at the Turnagain Pass SNOTEL1880′ elevation – we were at 21″ just a few days ago. One thing is for certain, we could use some colder temperatures with all this precipitation!

We update these charts daily. You can find them on our “weather history” tab under the weather menu item on our website!

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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