Seward & Southern Kenai Mtns

Archives
Issued
Fri, March 22nd, 2024 - 7:00AM
Expires
Sat, March 23rd, 2024 - 7:00AM
Forecaster
Daniel Krueger
Conditions Summary

Weekend Avalanche Outlook

Saturday, March 23 – Sunday, March 24

Bottom Line: A warm storm over the weekend might create new wind slabs up to 1′ deep that could be easy to trigger in mid to upper elevations. Wet loose avalanches are also possible as warm temperatures and rain will decrease the strength of the snowpack. Additionally, a persistent slab avalanche 1′ to 3′ deep is unlikely below 2,500′, but possible in the Carter Lake and Snug Harbor areas. March is a time where winter AND spring avalanche hazards exist, so it is important to adjust your travel plans if the snow and weather conditions increase the likelihood of triggering an avalanche.

Special Announcements

Turnagain Pass Avalanche Awareness Day – TOMORROW, March 23!
Swing by the Turnagain motorized parking lot between noon and 4pm to grab a hotdog, practice your beacons skills, chat with the forecast team, and possibly test out a demo snowmachine provided by local dealers. It will be an awesome time with awesome people!

Recent Avalanches

Recent Avalanches: Over the past week wet loose avalanches large enough to bury a person have been reported in the Seward and Lost Lake areas. These have been on south and east slopes. We have limited information, but it is possible other avalanches released last week.

Weather Recap: Last weekend a storm brought rain to around 2000′ and 1″ of new snow (0.3″ of SWE) was reported in the mountains. For the rest of the week, warm springtime conditions brought mostly sunny skies, moderate winds from the north, and temperatures in the 40s F to mid 20s F.

Weather Forecast: Over the weekend a storm tracking from the southwest is forecast to bring cloudy skies, strong winds, rain and snow to the Seward area. On Saturday expect strong southeast winds gusting 20 to 35 mph, rain switching to snow around 1500′ with a few inches of snow expected. Temperatures look to range from the low 40’s F near the highway to mid 20s F in the mountains. On Sunday cloudy skies are forecast to continue to bring strong ridgetop (20 to 30 mph) winds from the southeast to east with up to 5″ of new snow. Temperatures look to be slightly cooler (mid 30s F to mid 20s F) with the rain switching to snow around 1000′.

Avalanche Problem 1
  • Wind Slabs
    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

If the forecast verifies over the weekend, it could be possible to trigger a small wind slab avalanche up to 1′ deep in mid to upper elevations. Wind slabs will likely be forming over a sun crust on sunny slopes as well as on shaded slopes where old snow and new snow may form fresh wind slabs. These problems can be found below ridgelines, smooth rollovers (convexities), as well as in cross loaded gullies. If you see blowing snow, feel stiff snow over soft snow, see shooting cracks, or hear whumpfing, it is likely you are traveling on a wind loaded slope and it may be time to re-evaluate your terrain choices.

Cornices: Although it is unlikely over the weekend, warmer temperatures mixed with blowing snow can cause a cornice to fracture, triggering an avalanche from above. Look for cornices as you travel and try to limit time underneath them, especially if the wind is blowing snow off of the ridges. It is also recommended to avoid traveling on cornices as they can break further back than expected.

Avalanche Problem 2
  • Wet Loose
    Wet Loose
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.
More info at Avalanche.org

It will be possible to trigger a wet loose avalanche large enough to bury a person in steep slopes in mid to lower elevations. We are transitioning from winter to spring backcountry conditions where winter AND spring avalanche problems exist. The likelihood of you triggering a wet loose avalanche depends on how cold it freezes at night and how much rain the mid to lower elevations receives. If the temperatures remain above freezing overnight at these elevations and rain continues decrease the strength to the snowpack, this problem will become more likely. Indicators that the snow is becoming unstable are testing your boot to see if it sinks all the way into the snow, warmer temperatures at the car than expected, or you see natural avalanche activity.

Wet loose avalanches below the rocks and rollerballs. Seeing rollerballs rolling down the mountain are a good indicator that wet loose avalanches are becoming more likely. Photo 3.21.2024

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

There is still an outside chance of triggering a larger avalanche on a layer of weak snow buried 1′ to 3′ deep. This is becoming more unlikely because we are not getting concerning results in our snow pits and have not seen avalanches on these layers in more than three weeks. This is telling us that this problem is no longer widespread and is becoming harder to trigger. However, it is more likely to trigger an avalanche in the Carter Lake and Snug Harbor area as these layers are healing slower. Time will continue to heal these layers as well as traveling one at a time on steep slopes.

Weather
Fri, March 22nd, 2024

Weather Forecast Links:

NWS Point Forecast: Point forecast near Lost Lake.

NWS Avalanche Weather Guidance (AVG) forecast page: Zoom into the Anchorage bowl for special detailed winter forecast.

Windy.com Spot Forecast: Spot forecast for Lost Lake. (tip: scroll through models using the links at the bottom of the page, and change locations by clicking on the map).

Weather Stations

Grouse Creek Divide Snotel

Lost Lake Weather Station

Observations
Recent Observations for Seward & Southern Kenai Mtns
Date Region Location
04/16/24 Seward Observation: Lost Lake
04/10/24 Seward Observation: Lost Lake
04/03/24 Seward Observation: Snug Harbor
03/31/24 Seward Avalanche: Lost Lake
03/27/24 Seward Avalanche: Tiehacker Mountain
03/14/24 Seward Observation: Lost Lake via Snug Harbor
03/06/24 Seward Observation: Carter Lake
03/03/24 Seward Observation: Victor Creek, 1k – 1.6k elevation
02/29/24 Seward Observation: Carter Lake
02/26/24 Seward Avalanche: Mt Marathon
Riding Areas

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This is a general backcountry conditions summary. This advisory does not apply to highways, railroads or operating ski areas.