Thu, March 12, 2015 Turnagain Pass Avalanche Forecast

Thu, March 12th, 2015

Alpine

Above 2,500'

1 - Low

Treeline

1,000'-2,500'

1 - Low

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

Wind Slabs

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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

Lingering wind slabs from the strong Northwest winds earlier this week are littered about the mountains. They can be found to be a few inches thick to a foot thick. They vary from stiff and supportable to breakable and in some areas, still on the softer side. These slabs are a concern in steep complex terrain where even a small plate can knock you off your feet and pitch you somewhere you don’t want to go. One of my partners triggered one of these old pockets yesterday (a soft old wind slab ~10″ thick and 20′ wide in steep terrain photo below).

Avalanche Problem 2

Dry Loose

Dry Loose

Dry Loose avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

More info at Avalanche.org

Sluffs are VERY easy to trigger in steep terrain harboring loose surface snow. These are running faster and farther each day as the snow is becoming looser and looser with the cold weather. Sluff management is key. This means know where your sluff will go and stay out of the way of the debris. The volume of these sluffs is on the moderate side but, still plenty to washing-machine someone if caught on a sustained slope.

SEE VIDEO HERE. Photo above by John Sykes: Sluffs triggered in the Gold Pan basin yesterday (behind the Magnum and Cornbiscuit ridges and near the top of Bertha Creek)

As Heather mentioned yesterday, there is some great skiing and riding to be had at the Pass. Honing in on the dappled surface texture (or orange peel as some say) to suss out the soft snow works well. Also, despite the continued hazardous approaches from the parking lots, there is now a “Tincan Rappel” which makes accessing the goods on Tincan easier – thanks to the helpful citizen for the installation!

Additional Concern

Dry Loose

More info at Avalanche.org

Additional concerns include the

Weather

Thu, March 12th, 2015

Yesterday brought another round of sunny, cold and beautiful weather. Temperatures were right around 0F from the parking lot to the ridgetops.

For today, we should have the same sunny skies and cold temperatures. In fact, the Sunburst weather station has just recorded the lowest temperature for this season at 3am, -6F (runner up is -3F on January 25th). There is slight inversion in place with minus single digits in valley bottoms. Temps should rise to the teens at 1,000′ but stay near 0F on the ridgelines. The Northwest winds should remain in the 5-10mph range on the ridgelines today and may pick up a hair later this afternoon into the 15mph range.

Our next shot of snow (and warmer temperatures) is on Sunday and Monday. Until then, enjoy the sunshine!

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

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	6	0	0	43
Summit Lake (1400′)	1	0	0	9
Alyeska Mid (1700′)	8	0	0	28

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	-2	W	8	18
Seattle Ridge (2400′)	0	n/a	7	23

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

Riding Areas

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