Summit & Central Kenai Mtns

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

Weekend Avalanche Outlook

Saturday, Dec. 9 – Sunday, Dec. 10

Wind slab avalanches are our main concern for the weekend. A gusty storm on Thursday night brought 6” of new snow with strong easterly winds. With more snow and wind on the way this weekend, human-triggered avalanches will be likely and some avalanches could release naturally, up to 1-2’ thick and large enough to bury a person. We are also concerned that a person may be able to trigger an avalanche on weak snow buried deeper in the snowpack. 

 

Special Announcements

This is our second installment of weekend outlooks for the Summit area. We are excited to start organizing outreach events in the future as well as maintaining up to date information concerning motorized closures as more zones open across the Kenai.

Recent Avalanches

We triggered a small wind slab avalanche on December 4th on a test slope on the west side of Tenderfoot (details here). On December 7th I noticed several recent small natural avalanches on Gilpatrick. These most likely occurred during the winds that lasted from 12/4-12/7.

On Tuesday and Wednesday Summit experienced outflow winds gusting 20-30 mph from the northwest. Thursday’s storm brought 6” of snow overnight with sustained easterly winds of 10-20 mph and gusts to 30mph. Friday also had winds blowing 20-25 mph out of the east.

On Saturday, winds should average around 10-20 mph and gusts could exceed 25 mph from the east and northeast. Clouds will break up a little Saturday morning but we are expecting clouds to move back in later in the day, possibly bringing up to 2” snow from the afternoon into evening. It will be cold– around 0 F in the morning rising to the mid teens F at lower elevations with temperatures staying below zero F at higher elevations.

Sunday’s weather will become more active. Snow and winds are expected to start in the morning and pick up in the afternoon, bringing anywhere from 6” to 12” snow by Monday morning. Winds should start out of the south at 5-10 mph in the morning increasing to 15-25 mph from the east in the afternoon and evening. Morning temperatures will still be in single digits F but will warm to the mid 20’s F in the afternoon.

 

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

Thursday’s storm brought 6” of light snow to the mountains in Summit Lake. Unfortunately, that storm was accompanied by 10-20 mph winds from the east.  Looking into the weekend, winds and snow are expected Saturday and Sunday. These conditions will only further develop wind slabs that will increase in thickness and make them more likely to avalanche naturally and easier for people to trigger. If you plan on getting out over the weekend keep your head up and look for clues of wind transporting snow over ridges, into gullies, and below rollovers. As you are traveling, feel for stiffer snow and look for shooting cracks under your skis. These are great indicators telling you that there is the dangerous combination of a slab over softer snow. With wind slab problems, typically the better skiing is at lower sheltered elevations which will also have the most stable conditions. 

 

Cornices:  The ridgelines are likely to look a bit different after this week’s storm with some impressive cornices forming. These can be large triggers if they fail so limit exposure under them.

Testing a slope safely can tell you how stable the snow is. Here Mik tested this slope that was loaded from the wind and triggered an avalanche. 12.04.2023

 

Several recent small natural avalanches paths on Gilpatrick. 12.07.2023

 

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 two deeper weak layers in the snowpack that we are keeping our eyes on. The first is a layer of facets above the Thanksgiving crust identified in a pit at 3100’ (details here). These kinds of facet/crust combinations are notorious for ‘waking up’ down the road as the snow facets above and below these layers. The second is a layer of weak faceted snow buried at the ground in higher elevations. Given the poor structure we’ve seen, and poor stability test results in several recent pits, this is a concerning setup. Recent snow and wind are adding stress to the snowpack, pushing these layers closer to their breaking point. For now, the safe bet is to travel cautiously above 2,500’. We will keep you informed as we monitor these layers so stay tuned!

That layer of facets above the Thanksgiving crust was the layer that failed the stability test. 12.01.2023  

 

 

 

Weather
Fri, December 8th, 2023

Weather Forecasts

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.