Summit & Central Kenai Mtns

Archives
Issued
Fri, February 16th, 2024 - 7:00AM
Expires
Sat, February 17th, 2024 - 7:00AM
Forecaster
Mik Dalpes
Conditions Summary

Weekend Avalanche Outlook

Saturday, Feb. 17 – Sunday, Feb. 18

Bottom Line: Dangerous avalanche conditions exist in Summit Lake due to strong winds over the last 4 days and a buried weak layer in the snowpack. These conditions can be found at all elevations and all aspects, and it is likely a person could trigger a very large avalanche 1′ to 3′ deep on this layer. We recommend avoiding avalanche terrain by riding slopes less than 30 degrees and avoiding runout zones.

Special Announcements

Forecaster chat next Friday, February 23 from 5-6pm at the Seward Community Library and Museum community room. Come chat with us about the product we are producing called the “Weekend Avalanche Outlook,” and the state of the snowpack in Summit and Seward. We can also answer other questions you may have. More info Here.

Snowmachine access in the Kenai Mountains: Here is a map showing snowmachine access in Summit Pass. This is a great tool to better understand and travel in areas open to snowmachining. You can also download it to your phone to use in the field. This link provides information on how to use the winter recreation map layer.

Recent Avalanches

Recent Avalanches: An avalanche was triggered on Tuesday afternoon, February 13 by a group of three backcountry skiers on John Mountain. Two of the three people involved sustained injuries and the third did not survive. Our deepest condolences go out to the friends and family of the deceased. We have posted a preliminary accident report here and will publish a full report by the end of next week.

Several large natural avalanches were observed on the west face of Templeton and Butch Mountains on February 13 that were likely due to the wind loading. There was one smaller natural avalanche seen on the east face of Summit Mountain. The timing of this avalanche is unknown, but it may have been on February 15.

Weather Recap: Unusually springlike and windy conditions dominated the weather this week on the Kenai Peninsula. Average temperatures have been above freezing at the Summit Creek snotel weather station (1,400′) for the last four days. Average winds have been 10 to 25 mph primarily out of the east every day since last Friday. There was a large storm that moved through the Kenai Mountains last weekend, but Summit was on the light end of the precipitation accumulation totaling 3″ of new snow and 0.2″ of water on February 10.

Weather Forecast: The warm and windy pattern looks to continue through Saturday although winds should calm Saturday evening. Clouds should build tonight and remain partly to mostly cloudy through the weekend as a weak low pressure system approaches the Kenai. There is a chance the sun could poke through the clouds either day, which could warm things up dramatically if that is the case. Temperatures on Saturday look to be in the upper 20’s to low 30’s and ridgetop winds are forecast to be coming from the east at 25 to 35 mph gusting into the 40’s. By Sunday ridgetop winds should calm to 5 to 10 mph out of the east and temperatures are forecast to hover around freezing at 32 degrees F. The mountains may see a trace of snow Saturday and Sunday. There is a larger storm approaching Monday evening that could bring more snow to the area so keep an eye on the Turnagain forecast for more details.

Overview of John Mountain avalanche where accident occurred on February 13, 2024. Photo: 2.14, 2024

Avalanche Problem 1
  • 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 a dangerous weak layer of faceted snow buried 1′ to 3′ below the surface in the Summit snowpack which developed during the January cold spell. The avalanche that buried 3 skiers on John Mtn on February 13th occurred on this weak layer. Large to very large human triggered avalanches remain likely on this layer, especially in areas with recent loading from strong easterly winds. It is possible for avalanches to be triggered remotely on this type of weak layer, which means you can cause an avalanche from above, below, or to the side of a steep slope. This avalanche problem exists at all elevations and on all aspects of the compass, even in sheltered areas with good skiing conditions. This type of persistent slab may not produce any red flags before avalanching, but a whumpf or shooting crack are clear signs of unstable snow. To avoid this avalanche problem we recommend sticking to slopes less than 30 degrees and minimizing your time in runout zones of overhead avalanche paths. This layer may heal with time but patience is required to stay safe.

Snowpack at John Mountain on February 14, 2024

Avalanche Problem 2
  • 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

Strong easterly winds have been blowing for over a week and will continue to blow this weekend making both human triggered and natural avalanches likely. The snow being deposited by the wind is adding stress to the buried weak layer of facets described in problem one. This could make a wind slab avalanche larger than expected up to 3′ deep. We recommend avoiding avalanche terrain and sticking to low angle slopes less than 30 degrees to avoid both the wind and persistent slab problems.

Wind slab avalanches that are filling back in with new wind loading on Butch Mountain. Photo by Alex McLain 2.14.2024

Weather
Fri, February 16th, 2024

NWS Point Forecast: Point forecast for the Summit Lake area.

NWS Avalanche Weather Guidance (AVG) forecast page: Mountain weather forecasts for the region. Zoom in on the map to find point forecasts for Summit.

Windy.com Spot Forecast: Spot forecast for Summit (tip: compare models using the links at the bottom of the page).

 

Weather Stations

Summit Creek Snotel

AK DOT&PF Summit Lake Weather Station 

AKRR Ridgetop Weather Station

Observations
Recent Observations for Summit & Central Kenai Mtns
Date Region Location
04/10/24 Summit Observation: Manitoba
04/10/24 Summit Observation: Colorado
04/07/24 Summit Observation: Fresno
04/06/24 Summit Observation: Tenderfoot
04/04/24 Summit Observation: Gilpatrick North
03/27/24 Summit Observation: Colorado
03/24/24 Summit Observation: Near Tern Lake and Near Sixmile Creek
03/21/24 Summit Avalanche: Manitoba
03/21/24 Summit Avalanche: Summit eastside
03/21/24 Summit Observation: Johnson South
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.