Seward & Southern Kenai Mtns

Archives
Issued
Fri, January 5th, 2024 - 7:00AM
Expires
Sat, January 6th, 2024 - 7:00AM
Forecaster
Mik Dalpes
Conditions Summary

Weekend Avalanche Outlook

Saturday, Jan. 6 – Sunday, Jan. 7

Bottom Line: With up to 2’ of snow and strong winds forecast this weekend, we expect to see increasing avalanche danger with very dangerous conditions on Sunday. If the forecast verifies, it will be very likely for a person to trigger an avalanche in new and windblown snow, which could be 1-3’ deep and large enough to bury a person. These avalanches will be possible on Saturday, and will be very likely and very sensitive to trigger on Sunday. We recommend avoiding traveling on or below steep terrain as the storm picks up on Sunday.

Recent Avalanches

Recent Avalanches: There were two glide avalanches observed on January 3rd on Wrong Mountain that had occurred since last week’s outlook. They are located on the southeast face at about 2,800’. There were no other observed avalanches that we know of, but we did not get our eyes on the Lost Lake area this week. 

Weather Recap: It was a warm and stormy week in south central Alaska. A warm storm occurred Tuesday night into Wednesday (January 2-3)  bringing rain to about 1,300’. This storm brought at least 6” of new snow above the rainline and 0.6” snow water equivalent (SWE). This was followed by another colder storm (January 4-5) bringing 7” of snow and 0.8” SWE to sea level. Temperatures this week hovered around 32 F.

Weather Forecast: A couple of storm systems are bringing another round of snow and wind to the Seward zone this weekend. It is snowing and blowing in the mountains today, Friday, January 5th. Ridgetop southeast winds are sustained in the teens gusting in the 20’s mph. Precipitation should taper off by the time this outlook is posted and snowfall could be as much as 12” since 3 AM this morning. Saturday there is a brief lull between weather systems, temperatures in the Lost Lake area should be in the 25-30 degrees F range. Saturday afternoon another weather system moves in bringing up to 12” of new snow by Sunday afternoon. The peak intensity of this storm looks to be late Sunday morning with heavy snowfall and ridgetop winds in the 30-40’s mph gusting to 60 mph. The temperatures look to be 25-30 degrees F. The rain line could rise as high as 1,000’ during this storm.

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 as much as 1-2’ of new snow forecast this weekend, with periods of 30-40 mph southeast winds on the ridgetops, our primary concern will be storm and wind slab avalanches. Saturday it is possible a person could trigger a storm or wind slab 1-2’ deep, and the danger is expected to increase rapidly through the weekend. If the forecast verifies, Sunday looks to be the day that may have the most reactive avalanche conditions with another rapid load of snow and wind. These avalanches are likely to be found everywhere and could be 1-3’ deep. If Sunday proves to be a stormy day with low visibility, we recommend sticking to low angle terrain to give the snowpack time to adjust to its new load. 

If you are trying to get out Saturday during the lull between the storms, you can assess conditions by jumping or riding on a small steep test slope or digging a hand pit to see how Friday’s snow is bonding to the old snow surface. With the first round of precipitation tapering off this evening, it is looking like wind slabs may be the main concern for the first part of this weekend. Wind slabs look like smooth pillows of snow and feel firm beneath you. They are usually found below ridgelines, across gully features, and below rollovers. They may or may not produce a shooting crack or a whumpf.

Forecast snowfall totals from 3AM Friday to 3AM Saturday. Image courtesy of the NWS Anchorage office. Image can be found here. 1.5.24

Avalanche Problem 2
  • 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 are a few layers in the snowpack we are tracking. One is a layer of surface hoar that is now buried about 1’-1.5’ deep. This layer was observed throughout our forecast zones before it was buried earlier this week, but has not been especially reactive since it was buried. The second layer we are tracking is the Thanksgiving crust, now buried about 3-4’ deep in the Lost Lake and Snug Harbor areas. In some places, a weak layer has formed above the crust, which is a poor structure. However, we are not seeing results on either of these layers in our snowpits and we think it is unlikely a person could trigger an avalanche on either of these layers. That being said, we do not have very much information on these layers so we want people to have this in mind if you are getting into steep and rocky terrain once this weekend’s storm clears.

Snowpack in the V-max area showing poor structure, but good stability in this location with no results. 1.4.24

Additional Concern
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

 

 

 

Weather
Fri, January 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.