Seward & Southern Kenai Mtns

Archives
Issued
Fri, April 5th, 2024 - 7:00AM
Expires
Sat, April 6th, 2024 - 7:00AM
Forecaster
Andrew Schauer
Avalanche risk The Bottom Line

Weekend Avalanche Outlook

Saturday, April 6 – Sunday, April 7

Bottom Line: After receiving 2 to 3 feet of new snow this week and strong winds continuing into the weekend, wind slab avalanches will be the main concern for the next few days. These may be up to 2 feet deep or deeper. The most likely places to trigger an avalanche will be on steep slopes near ridgelines, convex rolls, or steep gullies. Look for the safest snowpack and best riding and skiing conditions in terrain that has remained sheltered from the winds. It will also be important to pay attention to wet snow avalanche problems as the sun heats the snow surface during the day.

Special Announcements

Avalanche Forecast Survey: Simon Fraser University is collaborating with US avalanche centers to better understand how useful avalanche forecast information is for trip planning. This research will help drive development of future avalanche forecast products. Click here if you are interested in participating in a 20 minute survey.

Fri, April 5th, 2024
Alpine
Above 2,500'
0 - No Rating
Avalanche risk
Treeline
1,000'-2,500'
0 - No Rating
Avalanche risk
Below Treeline
Below 1,000'
0 - No Rating
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

Recent Avalanches: We saw evidence of a widespread natural avalanche cycle from Snug Harbor to Lost Lake as well as across the valley on Mt. Tiehacker during the stormy weather that brought heavy snowfall and strong winds starting last weekend. Most of these avalanches were around 1 to 3 feet deep on average, and anywhere from 50 to 500′ wide, and were failing on wind-loaded slopes. It is likely the majority of these avalanches were failing at the interface between the storm snow and the older crust it was falling on.

Weather Recap: The mountains around Seward and Lost Lake recieved 2 to 3 feet of snow from last Saturday, March 30 to Monday, April 1. The storm was cold enough to deliver 18″ of snow to sea level during this time frame. This storm was accompanied by strong winds out of the south, which switched to the northwest after the snow stopped. Skies were partly sunny to mostly cloudy during the middle of the week with light winds. Temperatures were in the low to upper 20s F at upper elevations and low 30s to 40 F near sea level.

Weather Forecast: While we may see a few inches of snow over the weekend, the wind will be the main weather factor. Strong northwest winds are expected to continue Friday evening through early Saturday morning, with average speeds of 25 to 30 mph and gusts of 40 to 50 mph along ridgetops. Things are expected to calm during the day Saturday, before the wind shifts back to the east and picks up again on Sunday. Average wind speeds Sunday should be around 15 to 25 mph with gusts of 20 to 30 mph. It is looking like we should see some sun on Saturday, with mostly cloudy skies on Sunday. High temperatures are expected to be in the low 30s to 40 F with lows in the low 20s to low 30s F.

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

Wind is going to be the main factor to pay attention to this weekend. The northerly outflow winds we are currently seeing should continue through most of Friday night before calming early Saturday morning, but will be followed by increasing easterly winds  Saturday night into Sunday. This shift in direction will mean that we may find reactive wind slabs on all aspects by the end of the weekend, so it will be important to pay attention to surface conditions wherever you end up traveling. We’re not anticipating a whole lot of snow, but we already have plenty of soft snow on the ground that will be easily transported into senistive slabs.

Be on the lookout for fresh avalanches, snow blowing off ridgetops, and shooting cracks as clear signs of unstable snow. You can often assess these wind slab problems quickly by hopping off your snow machine or stepping off the skin track and getting an idea of what the snow on the surface feels like. Be wary of slopes with stiff snow on top of softer snow. The most likely places to run into trouble will be in steep terrain at upper elevations, especially below ridgelines or in cross-loaded gullies.

Persistent Slab Avalanches: Earlier in the week we saw multiple large avalanches failing on top of a crust during the most recent storm. From what we have been able to gather it seems unlikely that we will continue to see avalanches failing on this interface. However, crusts are notoriously difficult to predict. This may be worth keeping in mind before committing to big, steep terrain. It will take more time to assess this layer since it is buried 1-2′ deep or deeper in most places.

Natural avalanche on Tiehacker, seen Sunday 3.31.04.

The wind has been at work in the alpine all week, and will contine into this weekend. Photo taken near the Lost Lake weather station, 04.03.2023.

 

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 is looking like we may see more sunny weather on Saturday, along with mild temperatures. Be on the lookout for loose snow avalanches especially on steep southeast to southwest aspects as things heat up during the day. The first indicators will be roller balls or pinwheels releasing near rocks or trees. Keep your eyes on steep start zones overhead as surfaces heat up in the afternoon, and be ready to move to shaded slopes if you start to notice things becoming unglued.

This steep, rocky south-facing terrain is the kind of place we expect to see wet loose avalanches happening the earliest. Photo taken near V-max hill, Snug Harbor area, 04.03.2023.

Weather
Fri, April 5th, 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.