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Issued
Fri, March 8th, 2024 - 7:00AM
Expires
Sat, March 9th, 2024 - 7:00AM
Forecaster
Wendy Wagner
Avalanche risk The Bottom Line

The avalanche danger is MODERATE at all elevations. Tuesday’s new snow has not entirely bonded yet and there is still a chance of triggering a slab avalanche between 1 to 2 feet deep. The steeper and more wind loaded the slope, the larger the potential avalanche. Additionally, triggering a sluff on steep slopes with loose surface snow is likely. If the sun warms southerly aspects enough, watch for small wet loose avalanches.

SUMMIT/JOHNSON PASS: The snowpack in the central Kenai mtns is weaker than at Turnagain. There is still a chance a person could trigger a bigger avalanche on weak snow buried in the upper 2 feet of the snowpack.

Special Announcements

Turnagain Pass Avalanche Awareness Day – Saturday, March 23!
Swing by the Turnagain motorized parking lot between noon and 4pm to grab a hotdog, practice your beacons skills (we’ll have a small park set up), chat with the forecast team, and possibly test out a demo snowmachine provided by local dealers. This is a fun day designed to connect with our excellent backcountry community!

Fri, March 8th, 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
Sat, March 9th, 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
Sat, March 9th, 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

A couple skier triggered slab avalanches were reported yesterday. They were 1-2 feet deep, breaking in weak snow just under the new storm snow from a couple days ago. Neither slab propagated very widely. One was on Magnum ridge, photo below, and other on the lower slopes of Placer Valley, no photo. The skier who triggered the slab on Magnum was initially caught then able to gain control and ski out. If there were others we didn’t hear about, please let us know.

Skier triggered avalanche on the west face of Magnum yesterday. Big thank you to Alex Lee for passing along the photo and details of the avalanche. 3.7.24.

Avalanche Problem 1
  • Storm Slabs
    Storm Slabs
  • Aspect/Elevation
  • Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic (D4-5)
    Very Large (D3)
    Large (D2)
    Small (D1)
    Size
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.

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

The storm that ended a couple days ago deposited up to 14″ of low density snow at Turnagain Pass and closer to 20+” in areas of the Placer Valley. This snow fell on weak sugary older snow and once skies cleared, many natural avalanches were seen by folks out and about. Check out the photo below of a large natural avalanche in Skookum drainage. These avalanches released at the interface between the new and old snow and people were still able to trigger avalanches yesterday at this interface. With quiet weather in the forecast today (partly cloudy skies, light winds, and temperatures in the 20s F), triggering a slab avalanche 1-2′ thick that is composed of Tuesday’s storm snow is the main concern.

If you are headed out, keep a close eye our for cracking in the snow around you and any whumpfing sounds (collapsing in the snowpack). These are clues the new snow has not bonded in the area you’re traveling and triggering an avalanche is likely. Digging with our hand in the snow to see how much new snow there is and if it’s breaking off easily in less-cohesive snow underneath is a good way to know more about what we’re dealing with. Jumping on small test slopes should also be good ways to assess this questionable interface.

 

Very wide propagating storm slab in the lower Skookum drainage – zoom in on the crowns. This likely occurred at the tail end of the storm a couple days ago (March 5-6ish). This is a lower elevation slope (crowns around 1,500′ and debris around 200′). Thanks to Travis Smith for snapping the pic. 3.7.24.

 

Dry loose snow avalanches:  Steep slopes with loose surface snow are suspect for triggering dry sluffs. As always, pay attention to where your sluff will go and how much snow it’s entraining on the descent.

South facing slopes:  The sun has been able to warm up many south facing slopes the past couple days, which has formed a thin sun crust. If the clouds let enough sunshine through today, watch for moistening snow on the south aspects. Small wet loose avalanches could occur naturally in this case.

Weather
Fri, March 8th, 2024

Yesterday:  Partly cloudy skies were over the region yesterday with light variable winds. Temperatures reached the upper 20s F at the mid elevations and near 40F at sea level in the afternoon before cooling off over night. The Sunburst Webcam sunset was GREAT!

Today:  Partly cloudy skies with some some sunshine poking through is expected today. Winds are expected to be calm to light westerly along ridgetops. Temperatures should be a bit cooler than yesterday, rising to the mid 20sF at mid elevations and the mid 30s F at sea level.

Tomorrow:  Clouds are forecast to stream in tomorrow, Saturday, as another weather system begin to move in for Sunday and the early part of the week. Starting Saturday night light snow is expected to fall, accumulating 2-4″ by Sunday evening. For Saturday ridgetop winds are looking to remain light from the southeast, yet bump up in conjunction with the snowfall from the east (10-20mph).

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

Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 27 0 0 91
Summit Lake (1400′) 24 0 0 45
Alyeska Mid (1700′) 29 0 0 93
Bear Valley – Portage (132′) 30 0 0
Grouse Ck (700′) 30 0 0 64

RIDGETOP 24-hour data (6am – 6am)

Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 20 NE 7 25
Seattle Ridge (2400′) 24 SE 4 11
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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.