Mon, January 25, 2016 Turnagain Pass Avalanche Forecast

Mon, January 25th, 2016

Alpine
Above 2,500'

Moderate (2)

Treeline
1,000'-2,500'

Moderate (2)

Below Treeline
Below 1,000'

Low (1)

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

A lot of people are wondering if the earthquake shook loose any avalanches yesterday? Well, the answer is yes, but not anything too big or bad or ugly – that we know of. With ok visibility yesterday, it looked as though several chunks of cornice fell and some of these triggered small wind slab pockets below them.

Below is a photo from South facing Magnum Ridge:

Check out the many observations sent in to us yesterday – many of these were from the Alaska Avalanche School’s Level 2 course – thanks!

Avalanche concerns for today at the higher elevations (above 2,500′ where it is snowing) will focus on the new snow and wind. We have seen another 4-6″ of snow along with strong Easterly ridgetop winds overnight; this is on top of the 6″ from Saturday night. Today we are expecting an additional 2-6″ of snow with the moderate to strong winds remaining. Yesterday, wind slabs were stabilizing rapidly due to the warm temperatures and ‘sticky’ nature of the snow. We are expecting similar conditions for today. What to look for if visibility allows for travel above treeline:

How the winds have drifted the new snow from overnight and what sections of the slopes are loaded
Watching for shooting cracks
Jumping on wind loaded test slopes
Quick hand and pole pits to see how any new slab is shearing
Feeling for stiffer snow over softer snow

If you find cracking or any signs pointing to sensitive wind slabs steer clear of that slope. These slabs are sitting on a generally stable snowpack and not expected to step down into any deeper layers in the pack.

**However, shallow zones such as the Summit Lake area and South of Turnagain Pass harbor a variety of old weak layers in the pack. These have been mostly unreactive but something to keep in mind if a new load is placed on them. See the Summit Lake Summary from Saturday for more on this.

Although cornices got a good shake early yesterday morning, give these a wide berth as they could still be prime to fall.

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

Glide cracks continue to open and widen, yet we did not see any new releases yesterday. See video below from Corn Biscuit ridge (we were almost sure this thing was going to avalanche while we were up there…). As we keep mentioning, limiting time, or avoiding time altogether, under these things is highly recommended!

Closeup of a portion of the Corn Biscuit glide crack.

Weather

Mon, January 25th, 2016

Obscured skies along with pockets of blue holes covered the area yesterday. Winds were in the moderate range on the ridgetops, 15-20mph from the East. Intermittent light snowfall (rain below 1,000′) was seen with no accumulation.

Overnight, another warm and wet front has moved over us associated with a large low-pressure in the Gulf. Precipitation started falling around 9pm and as of 6am this morning, .5″ of rain has fallen below 1,500′ with 5″ of dense snow above treeline. The Easterly ridgetop winds have jumped as well, these are blowing in the 30’s mph with gusts in the 60’s. Temperatures are in the mid 30’s at 1,000′ and the mid 20’s F at 4,000′.

Today we should see cloudy skies with continued snowfall adding 2-6″ of dense snow above 2,000′ and ~.25-.5″ of rain below 1,800′. Ridgetop winds are slated to remain in the 20-30mph range from the East with stronger gusts and temperatures will stay warm…(mid 30’s F at 1,000′ and mid 20’s F on the ridgetops). Keep in mind with this weather pattern it will be possible to see more snowfall than predicted.

Tuesday, a break between systems will bring intermittent snow showers with some possible sunny breaks. Stay tuned.

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

	Temp Avg (F)	Snow (in)	Water (in)	Snow Depth (in)
Center Ridge (1880′)	32	3	0.5	90
Summit Lake (1400′)	35	1	0.1	27
Alyeska Mid (1700′)	33	2	.6	74

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	25	ENE	24	62
Seattle Ridge (2400′)	27	N/A	N/A	N/A

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 Thu, June 01st, 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	Closed May 15.
Placer River	Closed	Closed May 15.
Skookum Drainage	Closed	Will close to motorized use on April 1, 2023 per the National Forest Plan.
Turnagain Pass	Closed	Will close on June 1.
Twentymile	Closed	Scheduled closure May 1.
Seward District
Carter Lake	Closed	Scheduled closure May 1.
Lost Lake Trail	Closed	Scheduled closure May 1.
Primrose Trail	Closed	Scheduled closure May 1.
Resurrection Pass Trail	Closed	Closed to motorized use for the 2022/23 winter season per Forest Plan. Open next season.
Snug Harbor	Closed	Extended opening until May 15.
South Fork Snow River Corridor	Closed	Scheduled closure May 1.
Summit Lake	Closed	Scheduled closure May 1.