Sun, April 21, 2013 Turnagain Pass Avalanche Forecast

Sun, April 21st, 2013

Alpine
Above 2,500'

Low (1)

Treeline
1,000'-2,500'

Low (1)

Below Treeline
Below 1,000'

Low (1)

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

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

We do not have great conditions for wind slab development with little snow available for transport (much of the surface is in the form of crusts) and only up to an inch of new snow in the forecast. However, there are two things to keep in mind which will keep wind slab on the radar. First, winds have been predominantly out of the northwest for the past week but shifted around to an easterly direction yesterday and picked up overnight. And second, many northerly aspects still harbor loose faceted snow that could be blown into fresh drifts. So the question is, will the wind be strong enough and in the right direction to form slabs? It’s possible. For today, watch for signs of visible wind loading and cracking in the snow under you from a drift that may have formed earlier. Any fresh slabs should be shallow (~6″ at best) yet quite sensitive as they’ll likely be sitting on a slick surface.

Avalanche Problem 2

Dry Loose

Dry Loose

Dry Loose avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

More info at Avalanche.org

Fast running sluffs on steep northerly aspects have been the only avalanche activity we have seen or heard of for the past several days. This will be the case again today so sluff management continues in areas with loose faceted snow. Many slopes however sport varying degrees of sun crust and wind crust along with many many tracks.

With cloudy skies and cool temperatures in store today the threat of wet loose snow avalanches will be low.

Weather

Sun, April 21st, 2013

Yesterday marked the 11th day in a row with sunny skies, cold nights and no precipitation. We may break that streak today – but if we do it’s likely only in the cloud cover category. We have a weak low pressure system in the Gulf that is pushing clouds and a little bit of moisture in from the east. Overnight, temperatures have dipped to the mid 20’sF at most locations and the upper teens on the ridgelines with winds increasing from the east with averages ~13mph and gusts to 28mph.

Today, we may see a trace to an inch of snow down to 500′ and a rain/snow mix below. Daytime temperatures should rise into the 30’s at 1,000′ and mid 20’s on the ridgetops. The easterly winds look to remain in the 15-20mph range with occasional stronger gusts.

Tonight and into Monday we may see 1-2 inches of snow accumulation above 1,000′ and a rain/snow mix below. Temperatures look to be warm on Monday afternoon to the upper 30’s at ridgetops and 40’s at 1,000′ with mostly cloudy skies.

Below is a little recap of our season’s precipitation (Turnagain Pass SNOTEL data). We were catching up to average water numbers by February but have dropped off into the 75-80% of normal during our dry April to date.

I will issue the next advisory Tuesday morning, April 23rd.

Observations

Recent Observations for Turnagain Pass

Date	Region	Location	Observer
05/22/23	Turnagain	Avalanche: Tincan	Nick D'Alessio
05/12/23	Turnagain	Avalanche: Tincan, Sunburst, Magnum, Cornbiscuit	Heather Thamm
05/07/23	Turnagain	Observation: Tincan – Bear Tracks	CNFAIC Staff
05/05/23	Turnagain	Observation: Seattle Ridge	AS/ WW Forecaster
05/02/23	Turnagain	Observation: Cornbiscuit	Schauer/ Sturgess Forecaster
05/02/23	Turnagain	Observation: Seward Hwy Turnagain Pass	Joel Curtis
04/30/23	Turnagain	Observation: Magnum	Ayla, Kit Crosby, Barton
04/29/23	Turnagain	Observation: Tincan	John Sykes
04/28/23	Turnagain	Avalanche: Taylor Pass/Pastoral	Schauer/ Creighton Forecaster
04/28/23	Turnagain	Avalanche: Tincan	Andy Moderow

Riding Areas

Updated Sat, September 23rd, 2023

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	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Placer River	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Skookum Drainage	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Turnagain Pass	Closed	Scheduled opening on the Wednesday before Thanksgiving per Chugach National Forest plan. Subject to adequate snow cover.
Twentymile	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Seward District
Carter Lake	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Lost Lake Trail	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Primrose Trail	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Resurrection Pass Trail	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Snug Harbor	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
South Fork Snow River Corridor	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.
Summit Lake	Closed	Scheduled opening per Chugach National Forest plan December 1. Subject to adequate snow cover.