Fri, April 24, 2015 Turnagain Pass Avalanche Forecast

Fri, April 24th, 2015

Alpine
Above 2,500'

Moderate (2)

Treeline
1,000'-2,500'

Moderate (2)

Below Treeline
Below 1,000'

No Rating (0)

Alpine Above 2,500'		Moderate (2)
Treeline 1,000'-2,500'		Moderate (2)
Below Treeline Below 1,000'		No Rating (0)

Danger Scale:

No Rating (0)

Low (1)

Moderate (2)

Considerable (3)

High (4)

Extreme (5)

Avalanche Problem 1

Wet Loose

Wet Loose

Wet Loose avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

More info at Avalanche.org

Yesterday’s sunshine, calm winds and rapidly warming daytime temperatures triggered numerous wet loose avalanches on predominantly South and West aspects. We should expect a similar pattern today as partly cloudy skies and light winds are forecast. Yep, we are in a classic springtime melt-freeze cycle with a generally solid snowpack in the morning giving way to wet loose avalanches later in the day. The rule of thumb is, once the surface snow/crust becomes saturated to your boot tops (with skis/boards off) it’s time to head to a cooler aspect. There is still plenty of cold and dry snow, but it is at the upper elevations on Northerly aspects.

*If the winds stay light today, don’t be fooled if there is some cloud cover; thin clouds can create a type of ‘green house’ effect and warm all aspects, including North.

Photo on the left is from the North side of Tincan where a very large wet slide occurred sometime in the past 3 days. This slide is off a Northerly aspect and debris was reported to be 10-15′ deep. (Photo credit: Hunter McConnel). Photo on the Right are your classic wet loose avalanches in steep South facing terrain (Photo: Graham Predeger).

Avalanche Problem 2

Wind Slabs

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

More info at Avalanche.org

We know of one large slab avalanche, possibly a large wind slab, that released naturally in the past 48 hours. This avalanche (pictured below) is on a Westerly aspect across Turnagain Arm from around Seward Highway’s Mile Post 94, just East of Mount Alpenglow. The take home here is, although unlikely, triggering an old slab is not out of the question with our transitioning snowpack from winter to summer.

Fresh wind slabs may build at the upper elevations later today if we see an increase in South and East winds. Although there is plenty of loose snow available for transport, these are expected to be isolated and shallow and confined to Northerly aspects.

*The avalanche pictured is a reminder that even during times of low danger, we need to keep our safe travel habits alive and not become complacent; the main two being, exposing only one person a time and watching our buddies.

Recent slab off a West aspect across Turnagain Arm. (Photo credit: Graham Predeger)

Weather

Fri, April 24th, 2015

It was a brilliant day in the backcountry yesterday with sunny skies and light and variable winds. Temperatures at the upper elevations reached 32F and at 1,000′ the low 40’s F.

Another nice day is on tap today, however temperatures are not expected to get quite that warm (upper 20’s on the ridgetops and upper 30’s at 1,000′). Winds should pick up slightly to the 10mph zone from the East and South. We could see some high clouds filter in and out associated with a large low pressure over the Aleutians.

For the weekend, it looks like partly cloudy skies continue with light to moderate East winds. The low pressure over the Aleutians looks to track to our South with the moisture missing Southcentral.

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

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	37	0	0	72
Summit Lake (1400′)	30	0	0	14
Alyeska Mid (1700′)	36	0	0	45

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	29	VAR	4	14
Seattle Ridge (2400′)	28	n/a	8	22

Observations

Recent Observations for Turnagain Pass

Date	Region	Location	Observer
01/20/21	Turnagain	Observation: Sunburst	Johnston-Bloom / Roberts Forecaster
01/19/21	Turnagain	Avalanche: Cornbiscuit	Schauer/ Johnston-Bloom Forecaster
01/19/21	Turnagain	Avalanche: Sunburst and Tincan	CNFAIC Staff
01/19/21	Turnagain	Avalanche: Seattle Ridge	CNFAIC Staff
01/19/21	Turnagain	Avalanche: Tincan 2900′ SW aspect below Hippy Bowl.	Kris Marshall
01/18/21	Turnagain	Observation: Turnagain Pass Road Obs.	A Schauer Forecaster
01/16/21	Turnagain	Avalanche: Tincan Trees	A Schauer Forecaster
01/15/21	Turnagain	Observation: Sunburst	Schauer/ Wunnicke Forecaster
01/13/21	Turnagain	Observation: Tincan	Johnston-Bloom / Moderow Forecaster
01/13/21	Turnagain	Observation: Center Ridge Meadows	Alaska Avalanche School Rec Level 1 Roberts

Riding Areas

Updated Tue, January 12th, 2021

Status of riding areas across the Chugach NF is managed by the Glacier and Seward Ranger Districts, not avalanche center staff. Riding area information is posted as a public service to our users and updated based on snow depth and snow density to prevent resource damage at trailhead locations. Riding area questions contact: mailroom_r10_chugach@fs.fed.us

Area	Status	Weather & Riding Conditions
Glacier District
Johnson Pass	Open	No parking in turnaround at end of the road near the outhouse.
Placer River	Open	Early season conditions exist, including thin ice on rivers, swamps and lakes. Please do not ride along Railroad tracks. Cross tracks at 90 degree angle and clear the right of way.
Skookum Drainage	Open	Early season conditions exist, including thin ice on rivers, swamps and lakes. Please do not ride along Railroad tracks. Cross tracks at 90 degree angle and clear the right of way.
Turnagain Pass	Open
Twentymile	Closed
Seward District
Carter Lake	Open
Lost Lake Trail	Open
Primrose Trail	Open
Resurrection Pass Trail	Closed	Closed for the 2020/21 winter season.
Snug Harbor	Open
South Fork Snow River Corridor	Open
Summit Lake	Open