Tue, January 10, 2017 Turnagain Pass Avalanche Forecast

Tue, January 10th, 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

Blue skies, light winds and an uncharacteristically strong inversion continue to dominate our weather. Temperatures reached over 40F on some ridgetops yesterday, this is hard to believe from the single-digit cold air trapped in valley bottoms and parking lots. We got a report of a wet loose avalanche that ran in steep rocky terrain yesterday (photo below). With warm temperatures again today, these small wet loose slides, under rocks heated from the sun, are possible. If you decide to ride/ski on these steep South facing slopes, watch for surface warming in the top few inches of the snowpack and know that triggering a wet loose avalanche is possible.

Despite the ‘green light’ conditions, remember the snowpack has a poor structure on upper elevation slopes that have not avalanched and 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 warm temperatures and variability across the region, it’s not impossible. Keeping up with safe travel protocol is key (exposing one person at a time, grouping up in safe zones and having an escape route planned).

Small wet loose avalanche on South facing Tincan Proper yesterday. Likely triggered by rocks warming loose snow in very steep rocky terrain directly facing the sun. Thanks to Nick Crews for passing this on to us! Read more HERE.

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 possible this week: Continued warm temperatures at the upper elevations may enhance ‘glide’ in the snowpack. Watch for glide cracks to open up and a few may release. This pattern is similar to last week when 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) and Southerly slopes near Johnson Pass.

Weather

Tue, January 10th, 2017

STATE OF THE SNOWPACK??:

Below is a quick look at the snowpack, in terms of how much there is today compared to other years on this day. For snow depth, we are sitting at the 2nd thinnest January 10th, yet there are only data since 2004 when the sensor was installed. For SWE (Snow Water Equivalent), we are sitting at just over half of what we would normally be for this time of year. It has been 12 days since the last snowfall and it’s clear we are in need of a refresh!

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It was a sunny balmy day yesterday in the high elevations – temperatures at 4,000′ were right around 40F. This is quite a contrast to the cold frosty single-digit-air trapped in the valleys. Ridgetop winds yesterday were light and variable and skies were clear.

Overnight, the upper elevation temperatures remained in the high 30’sF while valley bottoms, sitting in the cold pool, are anywhere between -5 and +15F. Temperatures should rise a few degrees during the day, similar to yesterday. Ridgetop winds are expected to be light, 5-10mph from the Northwest and skies clear.

As we keep looking into the weather model “crystal ball” for the next precipitation event, it looks like we could get some cloudy skies and flurries for the weekend.

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

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	24	0	0	34
Summit Lake (1400′)	10	0	0	11
Alyeska Mid (1700′)	25	0	0	22

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	39!!	W	4	10
Seattle Ridge (2400′)	34	variable	3	8

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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