Sat, February 07, 2015 Turnagain Pass Avalanche Forecast

Sat, February 7th, 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

It has now been three weeks since the snowpack received any significant load. In those three weeks a total of 4” of snow fell in 1” increments. Temperatures have remained seasonable and winds have for the most part been calm.

What this all adds up to is a snowpack that is generally well adjusted. Triggering an avalanche is possible, but falls into the “outlier” category.

Low volume loose snow avalanches can be triggered on very steep (>40 degrees) sustained slopes. Watch your sluff and steer away from it, especially around terrain traps.

Isolated pockets of recently formed wind slab 6-8” in depth may be found in the higher elevations around the Girdwood Valley. If you make it into these areas, be on the lookout for stiff and hollow sounding snow on steep leeward slopes.

Glide cracks are scattered throughout the forecast area. Minimize time spent under glide cracks as they can release without the normal warning signs.

Aside from these snowpack issues you can expect to encounter firm and icy conditions on approaches (see photo below) with rocks and stumps being obstacles to avoid while exiting the mountains.

Icy Tincan approach

Weather

Sat, February 7th, 2015

A much anticipated wind event for Southcentral AK took place over the last 24 hours. Fortunately Turnagain Pass was spared in this outflow event. We found winds to be calm on ridgetops while in the field yesterday. Light plumes coming off of the higher peaks around the Girdwood, Twentymile, and Portage Valleys could be seen occasionally during the day.

Wind in mountainous terrain is not straightforward. Pictured here are plumes coming off a peak above Twentymile from North winds on Feb 6th. The wind anemometer at sea level shows winds out of the South. photo: Fitzgerald

Wind??

Temperatures were cold, with ridgetops averaging in single digits F.

Today will be a cold one, with temps to remain in the single digits F at ridgetops. Winds will be light out of the North at 5-10mph. We may see some high clouds streaming in from the East as a result of Low pressure spinning in the Gulf of Alaska.

The extended outlook is showing a welcome change in the overall pattern. High pressure that has dominated lately will break down and allow for moisture to make its way to the area. The next chance for accumulating snow will come by Tuesday or Wednesday of the coming week.

*Alyeska Mid station data 7am-2pm due to station malfunction.

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

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	12	0	0	31
Summit Lake (1400′)	0	0	0	7
Alyeska Mid (1700′)	10	0	0	21*

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	6	ENE	7	23
Seattle Ridge (2400′)	9	S	4	17

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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