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ARCHIVED - Forecasts expire after 24 hours.
Issued
Wed, March 27th, 2024 - 7:00AM
Expires
Thu, March 28th, 2024 - 7:00AM
Forecaster
Daniel Krueger
Avalanche risk The Bottom Line

The avalanche danger is MODERATE at all elevations. Below 2,000′ warmer temperatures will make it easy to trigger a wet snow avalanche on steep slopes. There is also a small chance of triggering a larger avalanche in mid to upper elevations on a buried weak layer 1-3′ deep.

Roof Avalanches: Roof avalanches will continue to release due to warm temperatures so keep your head up as you travel near roofs.

SUMMIT AND SEWARD: Wet snow avalanches are also a concern in these zones. We are not sure how high the snow surface froze but it is likely lower and mid elevation snow is saturated and likely to produced wet loose avalanches.

Special Announcements

Hatcher Pass:  Come check out the fundraiser film put on by the Hatcher Pass Avalanche Center at the BearTooth TOMMORROW! The Mountain in My Mind is the film, more details HERE!

Wed, March 27th, 2024
Alpine
Above 2,500'
2 - Moderate
Avalanche risk
Treeline
1,000'-2,500'
2 - Moderate
Avalanche risk
Below Treeline
Below 1,000'
2 - Moderate
Avalanche risk
Thu, March 28th, 2024
Alpine
Above 2,500'
2 - Moderate
Avalanche risk
Treeline
1,000'-2,500'
2 - Moderate
Avalanche risk
Below Treeline
Below 1,000'
2 - Moderate
Avalanche risk
Thu, March 28th, 2024
Alpine
Above 2,500'
2 - Moderate
Avalanche risk
Treeline
1,000'-2,500'
2 - Moderate
Avalanche risk
Below Treeline
Below 1,000'
2 - Moderate
Avalanche risk
0 - No Rating
1 - Low
2 - Moderate
3 - Considerable
4 - High
5 - Extreme
Avalanche risk Avalanche risk Avalanche risk Avalanche risk Avalanche risk
Travel Advice Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential. Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain.
Likelihood of Avalanches Natural and human-triggered avalanches unlikely. Natural avalanches unlikely; human-triggered avalanches possible. Natural avalanches possible; human-triggered avalanches likely. Natural avalanches likely; human-triggered avalanches very likely. Natural and human-triggered avalanches certain.
Avalanche Size and Distribution Small avalanches in isolated areas or extreme terrain. Small avalanches in specific areas; or large avalanches in isolated areas. Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. Large avalanches in many areas; or very large avalanches in specific areas. Very large avalanches in many areas.
Recent Avalanches

No new avalanches were reported yesterday. Cloudy skies and poor visibility have made it difficult to see if new avalanches occurred. However, with rain at lower elevations and warmer temperatures there is a chance natural avalanches have occurred especially in Portage and Placer. In Summit Pass, glide avalanches have been releasing for the past week.

Avalanche Problem 1
  • Wet Loose
    Wet Loose
  • Aspect/Elevation
  • 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.

Aspect/Elevation of the Avalanche Problem
Specialists develop a graphic representation of the potential distribution of a particular avalanche problem across the topography. This aspect/elevation rose is used to indicate where the particular avalanche problem is thought to exist on all elevation aspects. Areas where the avalanche problem is thought to exist are colored grey, and it is less likely to be encountered in areas colored white.

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

It has been 4 days since we have had prolonged freezing temperatures overnight below 2000′. When the snow surface freezes long enough to create a stout crust it decreases the likelihood that a wet avalanche can occur. If the surface did not freeze overnight, wet snow loses strength making it easy to trigger a wet loose avalanche on steep slopes. This problem will exist on all aspects, especially on southern aspects where up to a foot of saturated snow was found yesterday. These can be large enough to bury a person if they get carried into a terrain trap. If you get out today and the surface does not have a stout crust, your boot sinks above your ankle, and small test slopes trigger wet loose avalanches, it is likely to trigger a larger wet loose avalanche on bigger, steeper slopes.

Wet Slab: As temperatures remain warm, we are getting increasingly wary that there is a chance of natural wet slab avalanches especially on south aspects and lower elevations. Although humans essentially cannot trigger a wet slab avalanche, a large wet loose avalanche may trigger a wet slab. These can be large and destructive and run into lower angle terrain.

Wind Slab: There is a small chance you could trigger a lingering wind slab avalanche in steep wind loaded terrain above 2,000′ that formed over the few days. These will be larger in Girdwood and Portage/Placer as more snow fell in the past few days. Keep an eye out for cracking below you and stiff, wind deposited snow over soft snow, all indicators you are traveling on a wind loaded slope.

Additional Concern
  • Persistent Slabs
    Persistent Slabs
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
More info at Avalanche.org

Several buried weak layers 1′ to 3′ deep still exist across the forecast area. We think it is becoming unlikely to trigger a larger slab on a buried layer of surface hoar and facets. This will be even less likely if a stout crust freezes on the surface. Regardless, increase your margins for safety by exposing one person at a time in avalanche terrain and watching others from safe spots away from run out zones.

Weather
Wed, March 27th, 2024

Yesterday: Mostly cloudy skies with sunshine occasionally poking through the clouds. Winds were calm at the road and averaged 15 mph on ridgelines. Warmer temperatures at the highway averaged 31 F to 38 F with 42 F recorded in Portage Valley.

Today:  Mostly cloudy skies with valley clouds are forecast to slowly dissipate throughout the day. It is likely that the sun will poke out occasionally. Northeast winds are expected to be light (0 to 10 mph). Light snow is possible and will likely dissipate by the afternoon. Overnight temperatures barely dipped below freezing (31 F) in Turnagain Pass. Temperatures near sea level look to rise to the high 30s F to low 40s F.

Tomorrow: Cloudy skies are expected to break up a little, allowing the sun to shine in the afternoon. Light winds out of the north (0 to 10 mph) are forecast with little to no precipitation. Temperatures should be cooling slowly with Turnagain pass rising to low 30s F briefly. Girdwood and Portage also look to be cooler with temperatures in the mid 30s F.

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

Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 33 0 0 95
Summit Lake (1400′) 34 0 0 42
Alyeska Mid (1700′) 34 0 0 100
Bear Valley – Portage (132′) 37 Rain .27
Grouse Ck (700′) 36 0 0 63

RIDGETOP 24-hour data (6am – 6am)

Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 24 NE 8 15
Seattle Ridge (2400′) 28 SE 8 12
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This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area. This advisory does not apply to highways, railroads or operating ski areas.