Thu, April 29, 2021 Turnagain Pass Avalanche Forecast

Thu, April 29th, 2021

Alpine
Above 2,500'

Moderate (2)

Treeline
1,000'-2,500'

Moderate (2)

Below Treeline
Below 1,000'

Moderate (2)

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

Danger Scale:

No Rating (0)

Low (1)

Moderate (2)

Considerable (3)

High (4)

Extreme (5)

Avalanche Problem 1

Wet Loose
Almost Certain

Very Likely

Likely

Possible

Unlikely

Likelihood
Historic (D4-5)

Very Large (D3)

Large (D2)

Small (D1)

Size

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.

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

After a glorious 12-day stretch of sunshine, clouds streamed over the region yesterday evening and are slated to remain through today and into the beginning of tomorrow. There may be a few rain drops out there this evening, but those should stay closer to Whittier and Seward. Although temperatures are cooler, the cloud cover has limited the amount of overnight re-freeze; clouds tonight will likely limit the re-freeze for Friday as well. With temperatures in the upper elevations below freezing, those areas should have a solid crust, but it’s the mid and lower elevations that will be questionable. Hence, how much re-freeze has occurred? This is the question for anyone headed out to find some corn snow.

Keep in mind that triggering a wet loose avalanche is the main concern. This should be relatively easy to suss out as it completely depends on how wet the snow we are traveling on is. Slopes that are frozen, or those with just a few inches of soft snow over a hard crust are not an issue. But… once they warm enough that your boot or snowmachine starts to punch into 10+” of mush or so, it’s high time to head somewhere else. Either out of avalanche terrain or to slopes with less wet snow.

As for Wet slab avalanches, these remain on our mind, especially with the potential for a limited re-freeze and water slowly making its way down into the pack. For the next couple days this concern is mainly below around 3,000′ due to the colder temperatures in the high elevations. The rules are the same for this avalanche issue; steer clear of slopes with boot-top wet and saturated snow. Wet slabs are often triggered by a wet loose avalanche and can turn a small avalanche into a much larger and dangerous one.

Cornices: The past 12 days of warm temperatures is causing looming cornices to slowly droop. These are most unstable in the heat of the day, but should be suspect anytime. A cornice fall could trigger a wet avalanche on the slope below when conditions are ripe. Be aware to not accidentally travel onto one and limit any exposure under them.

Tincan’s west face, just above treeline. A lot of snow still remains out there! 4.27.21. Joe Kurtak.

Pastoral Peak, seen from Sunburst/Taylor Pass, last Friday, 4.23.21 by Troy Tempel.

Additional Concern

Wet Loose

More info at Avalanche.org

Glide cracks will be something to keep our eye on as long as snow covers the hillsides. These cracks can release into a destructive avalanche at anytime. It has been several days since we’ve heard of any cracks releasing. That said, there have not been many folks out in general to see them if there have been some failing. As always, watch for these and limit time, or avoid if possible, being under them.

Glide crack on Tincan. Photo taken Tuesday (4.27.21) by Joe Kurtak.

Weather

Thu, April 29th, 2021

Yesterday: Mostly sunny skies turned cloudy late in the day as a weak front pushed in from the south. Ridgetop winds were easterly in the 10-15mph range with gusts in the 20’sF during the day and have quieted down overnight. Temperatures climbed to the 40’sF in the mid elevations and have dropped back to the 30’s overnight.

Today: Mostly cloudy skies are expected to remain through today. A rain drop or two might fall but no measurable precipitation is expected in Girdwood or Turnagain Pass. Ridgetop winds are slated to shift northwesterly midday (5-10mph) as a trough pushes in from the west. This will bring in cooler temperatures and daytime high’s look to be in the low 40’sF at the lower and mid elevations and mid 30’sF along the ridgelines.

Tomorrow: Skies should begin to clear tomorrow with the potential for sunshine later in the day and into Saturday. Ridgetop winds look to be 5-15mph from the northwest Friday and switching back to the east (5-10mph) on Saturday. Temperatures will remain on the chiller side with high’s in the 40’sF at mid elevations and low’s in the 30’sF.

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

	Temp Avg (F)	Snow Depth (in)
Center Ridge (1880′)	40	89
Summit Lake (1400′)	42	27
Alyeska Mid (1700′)	42	99

RIDGETOP 24-hour data (6am – 6am)

	Temp Avg (F)	Wind Dir	Wind Avg (mph)	Wind Gust (mph)
Sunburst (3812′)	30	NE	13	28
Seattle Ridge (2400′)	33	SE	8	18

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.