Sun, January 11, 2015 Turnagain Pass Avalanche Forecast

Sun, January 11th, 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

Normal Caution

Normal Caution

Normal Caution means triggering an avalanche is unlikely but not impossible.

More info at Avalanche.org

I think the word is out that Turnagain Pass is not the place to find powder snow – this weekend anyhow… After a very warm storm rolled through Thursday saturating much of the snowpack up to 2,500′ and the surface layers up to 3,500′, the pack is slowly freezing from the top down. The rain wiped out much of the snow below 1,500′ and hiking is required from the parking lots at the Pass. Above 1,500′, the snowpack does get deeper quickly, but it’s the surface conditions that are the challenge. In short, the surface crust is mostly supportable, hard and slick. Beware that steep slopes have a slide-for-life character.

Where the crust ends and the soft snow begins is likely around 4,000′. If you are headed to these high elevations, assessing the snowpack is key. Keep your eye out for weak snow, such as buried surface hoar or facets, sitting under stiffer slabs. Finding a slab avalanche, most likely a wind slab, in these more remote and high elevations is possible.

For more details on snowpack and surface conditions, check out the several observations sent in yesterday from a level 2 avalanche course in the neighborhood. Thanks Alaska Avalanche School!

Avalanche Problem 2

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

Many glide cracks continue to open up in the forecast zone. During the day yesterday several new cracks were seen opening as well as existing cracks widen. None were reported to have avalanched but one avalanche instructor commented “We would not want to be below these glide cracks right now!”. That said, these are easy to recognize and avoidance is the best tactic considering their unpredictable nature and destructive potential. This is not the kind of avalanche a person can trigger, rather would be a case of being in the wrong place at the wrong time.

Photo below: Two avalanche students inspect a freshly open glide crack on Tincan ~2,800′ South facing. Notice the additional cracks further along the subridge. (Photo credit: Eeva Latosuo)

Photo below is of three “brown frowns” that have opened in the pat 48-hours (Eeva Latosuo).

Weather

Sun, January 11th, 2015

Yesterday was a mild day in the backcountry with partly cloudy skies, light Easterly winds and temperatures in the mid 30’s F at the mid elevations and low 30’s on the ridgetops. There has been no precipitation since Thursday’s 0.5-1″ of rain up to 3,000′.

Another mild day is in store for today. We should see partly cloudy skies with a slight bump in the Easterly ridgetop winds, into the 15mph zone. Temperatures look to remain near 30F on the ridgetops and the mid 30’s F at the mid and lower elevations.

Our next shot for precipitation is expected to arrive tomorrow afternoon in the form of rain below 2,500′ or so. This system will again usher in warm and windy conditions with moderate precipitation amounts. Stay tuned.

Looking further into the crystal ball (weather models) for later in the week and into the weekend, we will see a series of low pressure systems in the Gulf move through with showery precipitation. Slightly cooler temperatures are expected for Friday, which will help to lower the rain/snow line. However, warmer air looks to follow right behind for Saturday into Sunday, keeping the rain/snow line in the 2,000′ zone.

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

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	36	0	0	29
Summit Lake (1400′)	29	0	0	5
Alyeska Mid (1700′)	37	0	0	22.5

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	31	E	8	26
Seattle Ridge (2400′)	33	NE	12	27

Observations

Recent Observations for Turnagain Pass

Date	Region	Location	Observer
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
04/29/24	Turnagain	Avalanche: Turnagain aerial obs	Tully Hamer
04/27/24	Turnagain	Observation: Johnson Pass	Noah Mery
04/23/24	Turnagain	Observation: Turnagain Sunny Side	Travis SMITH
04/21/24	Turnagain	Observation: Bertha Creek	Anonymous
04/20/24	Turnagain	Avalanche: Spokane Creek	Schauer/ Mailly Forecaster
04/16/24	Turnagain	Observation: Cornbiscuit	Krueger / Matthys Forecaster

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