Summit & Central Kenai Mtns

Archives
Issued
Fri, April 5th, 2024 - 7:00AM
Expires
Sat, April 6th, 2024 - 7:00AM
Forecaster
Daniel Krueger
Conditions Summary

Weekend Avalanche Outlook

Saturday, April 6 – Sunday, April 7

Bottom Line:  This weekend looks to be filled with mostly cloudy skies, breezy ridgetop winds, and possibly a couple inches of new snow. In this case, small wind slabs will be the most likely avalanche issue a person would encounter. Be sure to watch pockets of wind drifted snow on slopes and in cross-loaded gullies. Additionally, wind slabs may be forming over a crust that that could make them easier for a person to trigger.

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Recent Avalanches

Recent Avalanches: On Tuesday, April 2, two small(ish) natural slab avalanches were seen on Fresno’s east face Tri-Tip Mtn’s west face (photo of Tri Tip below). These were around 1-1.5 feet deep and are believed to have failed on a buried weak layer. They most likely released after the storm on April 1. Additionally, a wet loose avalanche was seen on Tri-Tip’s steep west face. This likely released around April 2. It has been over a week since new glide avalanches have been reported in Summit.

Weather Recap: Last weekend 5″ to 10″ of new snow fell in Summit accompanied by strong east winds gusting 66 mph! On Monday, April 1, the storm started moving out with clouds breaking up and east winds gusting 30 mph. Tuesday and Wednesday had partly sunny skies with lighter winds. Another low pressure storm returned to Summit on Thursday and Friday with outflow winds gusting up to 30 mph and 1-2″ of new snow. Temperatures throughout the week at the highway averaged around freezing with a high of 41 F on Tuesday.

Weather Forecast: A front moving in from the northwest is expected to impact the Summit zone on Friday evening bringing outflow winds (30 mph gusts) and up to 2″ of new snow. On Saturday expect cloudy skies, lower valley clouds in the morning, and the potential for pockets of sunshine in the afternoon. Winds should turn southerly and blow 5-10 mph. Light flurries may deliver a trace of snow with temperatures ranging from mid 20s F to mid 30s F. Sunday looks to have a similar weather pattern except for ridgetop winds increasing into the 10-15mph range with gusts in the 20s.


A wet loose avalanche and a slab avalanche on Tri-Tip Mtn’s west slope. The wet loose likely occurred on April 2 when the sun came out in the afternoon. We are unsure if the slab avalanche failed on a buried weak layer or not. Photo 4.2.2024

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

As of Thursday, the general snow surface at Summit had surface crusts in the lower elevations but above 2,000′ there was 5-8″ of loose surface snow over an older melt-freeze crust. Friday evening, moderate outflow winds from the northwest and possibly a couple inches of new snow are expected in Summit. If the winds verify, small fresh wind slabs 6-12″ deep could form and be easy to trigger in the mid to upper elevations. Wind slabs form from blowing snow being deposited below ridgelines, convex rollovers, and cross loaded gullies. Typically, they are less concerning after 48hrs, however if they are deposited over a crust, it may take them longer to stabilize. Shooting cracks beneath your feet or machine is a clue you are traveling on a wind slab. Another way to assess a wind slab is by jumping on small test slopes to see if it cracks underneath you. Red flags such as blowing snow on the ridges are also indicators that snow is being transported into wind slabs. As the weather improves over the weekend, be wary of new or lingering wind slabs if you choose to head into avalanche terrain.

Wet Loose Sluffs:  If daytime warming is enough to melt the loose surface snow, or any existing sun crusts, then expect damp or wet loose sluffs to occur. Steep rocky southerly terrain is where this type of avalanche is common.

Persistent Slab: There are several old buried weak layers in Summit along with a crust buried beneath the storm snow from March 30 to April 1st (4″ to 12″ deep). This crust has been identified up to 2,700′ and may be higher. Several avalanches occurred in Turnagain Pass that failed on weak snow just over this crust, but we have not seen that at Summit. This is most likely because Summit only had around 8″ of snow compared to 24″ at Turnagain. As far as the old buried weak layers, it’s possible one of the avalanches seen this week released in one of them. We will keep tracking the snowpack and if a big storm hits or a major warmup, these layers may become more concerning.

 

Tri-Tip Mtn with evidence of wind loading. Below cornices are places where wind slabs likely form as well as below the “white line” of the cross loaded gully. Photo 4.2.2024

Weather
Fri, April 5th, 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
05/05/24 Summit Avalanche: Manitoba and Surrounding Areas
04/25/24 Summit Observation: Road Survey – Seward Highway Tern Lake to Portage
04/23/24 Summit Avalanche: Tenderfoot
04/20/24 Summit Observation: Tenderfoot
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
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.