Seward & Southern Kenai Mtns

Archives
Issued
Fri, December 8th, 2023 - 7:00AM
Expires
Sat, December 9th, 2023 - 7:00AM
Forecaster
Mik Dalpes
Conditions Summary

Weekend Avalanche Outlook

Saturday, Dec. 9- Sunday, Dec. 10

This is a heads up weekend Seward riders!  Our main concerns for avalanches will be both storm slabs and wind slabs.  With up to 2 new feet of snow by Sunday morning, which is a large load in a short amount of time, it could be easy for a person to trigger an avalanche on slopes steeper than 30 degrees.  These avalanches could be big enough to bury a person.  This is a weekend to stick to low angles and let the snowpack adjust to its new load.  If choosing to travel in avalanche terrain, expert level snowpack assessment is recommended.

Special Announcements

Motorized Areas: As of Friday, December 7th, there is between 8-12 inches of snow at the Lost Lake, Primrose, and Snow River trailheads. The Seward Ranger District will be assessing conditions regarding opening these zones to motorized use on Monday, December 12th. Areas currently open are Snug Harbor, Resurrection, Johnson Pass, and Turnagain Pass. Check the ‘Riding Areas’ tab (under ‘Resources’) for updates.

Recent Avalanches

The last known avalanches in the Seward area occurred during the November 29-30 storm. This storm deposited 2’ of snow in the alpine.  These avalanches were widespread loose snow avalanches releasing naturally in steep rocky terrain.  

An outflow wind event occurred this week that began the morning of Monday, December 4th and lasted through the morning of Thursday, December 7th.  The Lost Lake weather station is not currently operating, but the winds were likely 20-30mph with gusts in the 40-60’s from the north.  On Thursday, December 7th a cold storm brought around a foot of new snow to the Seward zone. The Grouse Creek weather station (mile 12 on the Seward Highway) at 700’ received 1.3” of water and 11” of reported snow. The Cooper Lake weather station at 1,200’ received 10” of snow from this colder storm.  This tells us that the precipitation amount was widespread throughout the Seward zone.  Ridgetop winds during this storm were generally out of the south and east.  

This weekend an active weather pattern is forecast with clouds building Friday evening and bringing 2-4” of snow to the mid and upper elevations by early Saturday morning.  Temperatures should climb into the teens and snow showers should continue through Saturday with another 4-6” possible by early Sunday morning.  This would be a total of almost 2’ of new snow since Friday if the storms verify.  On Sunday another pulse of moisture will arrive bringing potentially larger amounts of snow in the range of 12” or more by Monday morning.  Temperatures look to increase Sunday and climb into the mid 20’sF at 2,000’.  Snow line should increase to around 500’ Sunday evening.  The winds with this storm look to be moderate at times from the south and east.  The storms are forecast to keep coming this week potentially bringing 1-2′ of additional snow.

Avalanche Problem 1
  • Storm Slabs
    Storm Slabs
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.
More info at Avalanche.org

With almost 2’ of new snow in the mountains forecast by Sunday morning, avalanches will be expected.  The winds from last week created a smooth surface on the snow (which can act as a bed surface), which now has at least 12” on it from the December 7th storm, with another 8-10” that should fall tonight and tomorrow with wind speeds increasing both Friday and Saturday nights. This is a large amount of weight on the snowpack in a short amount of time.  Avalanches in the new snow could be easy for a person to trigger. They could be storm slabs in areas sheltered from the winds, or wind slabs in areas that see wind loading. These types of new snow avalanches could be big enough to bury a person and could be found everywhere.  

Watching for the common Red Flags will be important this weekend. These are signs of recent avalanches, cracks that shoot out from your machine, board, or skis, and whumpfing sounds. The snowpack could give you feedback that it’s unstable if you jump on a test slope (that doesn’t have consequences) or dig a hand pit to see if the storm snow is sticking to the older snow. However, the lack of feedback doesn’t always mean it is good to go.  Because the winds should shift direction throughout the weekend and can vary with terrain features, there’s a good chance that fresh wind slabs will be forming too.  These can be identified by looking for new cornices, large pillows of snow below ridge lines or across gully features, or areas that sound hollow or feel firmer beneath your feet or machine.  This is a good time to keep slope angles below 30 degrees until the snowpack can adjust to its new load. These types of new snow avalanches typically need 24-48 hours to adjust and bond to the older surface below. 

Smooth surface created by the wind event on Mount Alice in Seward with some sastrugi and goat anti-tracks.  12.07.2023

Snowpack at 2,500′ on Mount Alice.  12.07.2023

 

Forecasted snow from 3AM Saturday, December 9 – Sunday, December 10, 2023.

Weather
Fri, December 8th, 2023
Fri, December 8th, 2023

Weather Forecasts

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.