Mon, January 06, 2014 Turnagain Pass Avalanche Forecast

Mon, January 6th, 2014

Alpine

Above 2,500'

3 - Considerable

Treeline

1,000'-2,500'

3 - Considerable

Below Treeline

Below 1,000'

3 - Considerable

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

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

The snowpack received a serious shock over the weekend. Over a foot of new snow fell in a short period of time on Saturday night Jan. 4th. This resulted in widespread natural avalanching throughout the forecast area. High winds have eroded the snow near many of the areas that have avalanched, making it hard to see this evidence. Yesterday we were able to see this evidence but it was not blatantly obvious.

What we do know is that the snowpack still has a weak foundation. Time will allow the snowpack to adjust to this newest load to some degree. However, it has been only one day since we have had significant natural avalanche activity. The snowpack simply needs more time to adjust. The consequences of triggering an avalanche right now are potentially severe.

Dense slabs ranging between 1-3 feet deep are laying in wait for the right trigger. This may come in the form of a large group, or it may just take one person to hit a thin spot in the slab. Now is an important time to recognize and avoid likely trigger points. Areas of shallow snow, convexities and steep slopes should be avoided today.

Below is an image of one of many large natural avalanches that occured over the weekend.

Todd's

Avalanche Problem 2

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

New snow, warm temperatures and moderate wind (out of the East) will make it possible for humans to trigger shallow new wind slabs in steep terrain. These slabs on their own will not be large. However, triggering one of these newly formed slabs will have the potential to trigger deeper weak layers in the snowpack. It will be important to avoid steep slopes especially in areas receiving 6 or more inches of new snow and wind today.

Weather

Mon, January 6th, 2014

In the past 24 hours a trace of new snow has fallen on Turnagain Pass. Girdwood valley has picked up another 3-5 € of snow. Temperatures climbed overnight with ridge top stations in the high 20s F with the Turnagain Pass SNOTEL (1,880′) showing an overnight high of 36 F. Winds at the Sunburst station have been light to moderate out of the East averaging 18 mph.

Today expect cloudy skies and snow showers mainly in the first half of the day. Snow accumulation of 4-6 € are possible. Ridgetop winds will be out of the East at 25-30 mph. Temperatures will remain mild, in the low to mid 30s F at 1,000′.

The weather pattern to our South and West is complex. Computer models are doing a poor job of projecting weather beyond today. Expect unsettled weather over the next several days with modest precip amounts and generally mild temperatures.

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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