Wed, January 24, 2024 Turnagain Pass Avalanche Forecast

Wed, January 24th, 2024

Alpine

Above 2,500'

2 - Moderate

Treeline

1,000'-2,500'

2 - Moderate

Below Treeline

Below 1,000'

1 - Low

Thu, January 25th, 2024

Alpine

Above 2,500'

2 - Moderate

Treeline

1,000'-2,500'

2 - Moderate

Below Treeline

Below 1,000'

1 - Low

Thu, January 25th, 2024

Alpine

Above 2,500'

2 - Moderate

Treeline

1,000'-2,500'

2 - Moderate

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.

Recent Avalanches

No new avalanches have been reported in the past several days.

Avalanche Problem 1

Glide Avalanches
N E S W NW NE SE SW

Aspect/Elevation
Certain

Very Likely

Likely

Possible

Unlikely

Likelihood
Historic (D4-5)

Very Large (D3)

Large (D2)

Small (D1)

Size

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.

Aspect/Elevation of the Avalanche Problem

Specialists develop a graphic representation of the potential distribution of a particular avalanche problem across the topography. This aspect/elevation rose is used to indicate where the particular avalanche problem is thought to exist on all elevation aspects. Areas where the avalanche problem is thought to exist are colored grey, and it is less likely to be encountered in areas colored white.

Likelihood of Avalanches

Terms such as "unlikely", "likely", and "certain" are used to define the scale, with the chance of triggering or observing avalanches increasing as we move up the scale. For our purposes, "Unlikely" means that few avalanches could be triggered in avalanche terrain and natural avalanches are not expected. "Certain" means that humans will be able to trigger avalanches on many slopes, and natural avalanches are expected.

Size of Avalanches

Avalanche size is defined by the largest potential avalanche, or expected range of sizes related to the problem in question. Assigned size is a qualitative estimate based on the destructive classification system and requires specialists to estimate the harm avalanches may cause to hypothetical objects located in the avalanche track (AAA 2016, CAA 2014). Under this schema, "Small" avalanches are not large enough to bury humans and are relatively harmless unless they carry people over cliffs or through trees or rocks. Moving up the scale, avalanches become "Large" enough to bury, injure, or kill people. "Very Large" avalanches may bury or destroy vehicles or houses, and "Historic" avalanches are massive events capable of altering the landscape.

Signal Word	Size (D scale)	Simple Descriptor
Small	1	Unlikely to bury a person
Large	2	Can bury a person
Very Large	3	Can destroy a house
Historic	4 & 5	Can destroy part or all of a village

More info at Avalanche.org

Another clear and cold day is on tap with light westerly winds. The snow surface is old and tired, but becoming softer as the clear days go by. Until the weather takes a turn, our avalanche concerns are status quo. This means generally LOW danger for human triggered avalanches and MODERATE danger for that randomly releasing glide crack in a well-traveled location.

The good news is most glide cracks are easy to see and avoid. If your route does take you under these, it’s good to go one at time, watch the slope above, and go fast. Cracks can exists for months before releasing. Two years ago, a group descending the common route down Seattle Ridge under Repeat Offender was overrun by a glide avalanche with one person caught, buried, and rescued by their group. That crack loomed above the motorized uptrack for the entire season before avalanching in late April, similar yet larger to the ones that are there now.

Other than the glide avalanche concern, we are in a Normal Caution regime for human triggered avalanches. Cornices are slowly peeling away from ridgelines so we want to keep giving them a wide berth. The surface snow is becoming looser (faceting) with the clear weather and sluffs should be expected on steep slopes. There are always varying degrees of wind effect in the high exposed terrain. Small wind slabs in steep rocky terrain are something to watch for.

Weather

Wed, January 24th, 2024

Yesterday: Mostly clear skies, light westerly winds (~5mph), and cold temperatures (-15 to +15) were seen yesterday.

Today: Another carbon copy day is expected weather-wise. Mostly clear skies are expected with light westerly ridgetop winds (5-10mph). Temperatures are warming above the cold air inversion into the 20-25F range while valley bottoms should remain between -15 and 0F.

Tomorrow: Another clear and cold day is expected tomorrow, yet ridgetop winds look to bump up slightly from the northwest (5-15mph). Looking ahead, a chance for some clouds on Friday and a few inches of snow could occur on Saturday through Monday. Models are saying 2-6″ at this point with temperatures remaining cold, 0-15F.

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

	Temp Avg (F)	Snow Depth (in)
Center Ridge (1880′)	7	77
Summit Lake (1400′)	-7	n/a
Alyeska Mid (1700′)	6	75
Bear Valley – Portage (132′)	-11	–
Grouse Ck – Seward (700′)	0	51

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	18	W	6	17
Seattle Ridge (2400′)	18	NW	1	3

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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