Mon, March 07, 2016 Turnagain Pass Avalanche Forecast

Mon, March 7th, 2016

Alpine
Above 2,500'

Moderate (2)

Treeline
1,000'-2,500'

Low (1)

Below Treeline
Below 1,000'

No Rating (0)

Alpine Above 2,500'		Moderate (2)
Treeline 1,000'-2,500'		Low (1)
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

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

It was another spring-like day in the backcountry yesterday with bluebird skies and an opportunity for replenishing vitamin D stores. Today, cloud cover has moved back in but there could be some breaks here and there. We have 1-2″ of snow on tap with moderate Easterly winds. This is not enough snow to be a concern on its own but the reactive wind slabs from yesterday, as well as a bump in wind today, will keep wind slab avalanches on the docket. Loose snow sluffs and cornices will also remain on the docket.

Wind slabs:
Wind slabs that we are seeing and hearing about in the Turnagain Pass zone have been shallow 6-10″, scattered around ridgelines, and not packing too much punch. However, in the Girdwood Valley and North where more snow fell, slabs are reported to be thicker.

If you are headed out today, watch for:

1) Stiff snow on the surface of the snowpack
2) Winds actively loading slopes (there may be just enough wind in the forecast to form fresh slabs at upper elevations)
3) Cracking in the snow around you
4) Surface texture and hints that slopes are wind loaded

Cornices!: Give these a wide berth, wider than you think.

Sluffs: Watch your sluff. These are entraining several inches of surface snow and could get quite large in large terrain.

Photo below: Wind slab avalanche triggered by a skier yesterday. This avalanche was between the Magnum and Cornbiscuit ridgelines in an area called Superbowl. Skier was not caught and the slab itself was quite small, 6-10″ thick, yet did propagate down the ridge and entrain a bit of sluff as it ran.

Avalanche Problem 2

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

As long as glide cracks keep moving and breaking up our snowpack we will keep mentioning them. The picture below shows an oblique view of the large cracks on Cornbiscuit’s SW face. Folks have been wisely staying out from under them and, in this particular case, putting the skin track on the NW ridge.

We have not seen a glide avalanche in the Turnagain Pass zone for several days, however we do see these cracks continue to move and open. Limiting time under these, if your route must take you there, continues to be wise.

Photo: Oblique view of the glide cracks on Cornbiscuit’s SW face.

Weather

Mon, March 7th, 2016

Sunny skies greeted the many backcountry users along Turnagain pass yesterday. Winds were light from the Northeast on the highest peaks and it was downright warm with temperatures reaching 30F at the upper elevations and 45F along the road.

Overnight, winds have bumped up slightly (10-15mph from the East) and cloud cover has moved in. There is a very weak disturbance moving over through the day and we could squeak out 1-2″ of snow above 1,000′ today, with rain below, and another 1-2″ tonight. Cloud cover could also break apart is areas, providing for better visibility. Winds are slated to remain moderate in the 15-20mph range from the East along the ridgelines. Temperatures should be warm again, mid 30’s at 1,000′ and the mid 20’s on the ridgetops.

For Tuesday, another band of clouds and wind are on tap as a low pressure system in the Gulf moves North and begins to impact our region.

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

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	35	0	0	137
Summit Lake (1400′)	35	0	0	44
Alyeska Mid (1700′)	32	0	0	108

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	28	NE	7	17
Seattle Ridge (2400′)	30	–	–	–

Observations

Recent Observations for Turnagain Pass

Date	Region	Location	Observer
04/10/21	Turnagain	Observation: north sides	lance breeding
04/09/21	Turnagain	Observation: Girdwood to Turnagain Road Observations	W Wagner Forecaster
04/05/21	Turnagain	Avalanche: Resort bowl Seattle creek head wall	Clint Kyffin
04/04/21	Turnagain	Observation: Center Ridge	Andy Moderow
04/03/21	Turnagain	Observation: Repeat Offender – Seattle Ridge	Troy Tempel
04/02/21	Turnagain	Observation: Seattle Ridge	Wagner / Schauer Forecaster
04/01/21	Turnagain	Observation: Pete’s	Schauer/ Cullen Forecaster
03/31/21	Turnagain	Observation: Tincan	Schauer/ Rothman Forecaster
03/30/21	Turnagain	Observation: Eddies	Johnston-Bloom / Kinney Forecaster
03/30/21	Turnagain	Observation: Sunburst North	lance breeding

Riding Areas

Updated Thu, April 01st, 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	Please do not ride along Railroad tracks. Cross tracks at 90 degree angle and clear the right of way.
Skookum Drainage	Closed	The Skookum Valley is closed to snowmachines. This closure occurs annually on April 1 as per the CNF Forest Plan.
Turnagain Pass	Open
Twentymile	Open	Please do not ride along Railroad tracks. Cross tracks at 90 degree angle and clear the right of way.
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