Wed, January 11, 2017 Turnagain Pass Avalanche Forecast

Wed, January 11th, 2017

Alpine

Above 2,500'

1 - Low

Treeline

1,000'-2,500'

1 - Low

Below Treeline

Below 1,000'

1 - Low

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

High pressure continues to dominate our weather pattern and not much is expected to change today with the exception of temperatures cooling throughout the day. The inversion is forecasted to break down as cold air pushes into the region.

It is always important to keep in mind that LOW avalanche hazard does not mean NO avalanche hazard. If heading out into the mountains today remember the snowpack has a poor structure on upper elevation slopes that have not avalanched and that were loaded by past winds (mainly North and East aspects). Hard wind slabs sit on faceted snow and/or buried surface hoar. Triggering a more dangerous slab that breaks in these layers is unlikely, however with the variability across the region, it’s not impossible. Thin rocky areas and steep convexities with poor snowpack structure are most suspect. As always practicing safe travel protocol is key (exposing one person at a time, grouping up in safe zones and having an escape route planned). Looking at potential consequences of even a small slide in complex steep terrain is an important consideration.

Buried surface hoar found in a pit on Repeat Offender yesterday. 1.10.17. This layer was not reactive but still intact.

Additional Concern

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 this week? Continued warm temperatures at the upper elevations over the past couple days may have enhanced ‘glide’ in the snowpack. Watch for glide cracks opening up and always avoid spending time underneath as they may release. Last week 3 glide cracks released. Known cracks exist on the South face of Eddie’s, Goldpan (behind the Magnum ridge), East face of Seattle Ridge (Northern end), Main Bowl and Southerly slopes near Johnson Pass. Anecdotally we have been observing cracks releasing as temperatures cool after a warm up. Today might be one of those days.

Glide cracks in Main Bowl. 1.10.17

Weather

Wed, January 11th, 2017

Yesterday was clear, sunny and calm. The inversion was in place with ridge top temperatures above freezing and valley bottoms in the single digits. Overnight temperatures cooled slightly in the Alpine.

Today is forecasted to be similar with the exception of the inversion breaking down and cooling throughout the day into tomorrow as Arctic air moves in.

Tomorrow will be colder and clouds are actually in the forecast tomorrow night in advance of a chance of snow Friday. Fingers crossed for actual accumulation. Timing and amounts of precipitation are still TBD.

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

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	23	0	0	34
Summit Lake (1400′)	10	0	0	11
Alyeska Mid (1700′)	26	0	0	22

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	32	WSW	6	15
Seattle Ridge (2400′)	32	variable	2	8

Observations

Recent Observations for Turnagain Pass

Date	Region	Location	Observer
04/16/24	Turnagain	Observation: Cornbiscuit	Krueger / Matthys Forecaster
04/15/24	Turnagain	Observation: Taylor Pass	John Sykes Forecaster
04/15/24	Turnagain	Observation: Seward Highway – Tern Lake to Portage	Joel Curtis
04/14/24	Turnagain	Observation: Sunburst	T. Olsen-Lund, R. Sullivan I. Adams
04/14/24	Turnagain	Observation: Turnagain Pass Snomo	K. Gallaher
04/13/24	Turnagain	Observation: Spokane Creek	Everet Megli
04/11/24	Turnagain	Observation: Tincan	John Sykes Forecaster
04/10/24	Turnagain	Avalanche: Seattle Ridge	Schauer/ Keeler Forecaster
04/10/24	Turnagain	Observation: Cornbiscuit South Face	Todd Kelsey
04/10/24	Turnagain	Avalanche: Tincan	N. Dumont J. Carlberg

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