This is archived information related to an avalanche fatality in Alaska on Feb 13, 2024. The US Forest Service publishes a ‘Weekend Avalanche Outlook’ for Summit Pass, where this accident took place on Feb 13. The most recent Outlook was issued on Friday, February 9, and was valid from February 10 to 11. The closest daily avalanche forecast zone is for Turnagain Pass, which is 15 miles to the northeast. Although different avalanche danger can occur between these areas, on the day of the avalanche similar avalanche conditions existed. Both of these products are archived below. US Forest Service Weekend Avalanche Outlook Summit & Central Kenai Mtns, Alaska Issued: Fri, February 9th, 2024 - 7:00AM Expires: Sat, February 10th, 2024 - 7:00AM Forecaster: Daniel Krueger Conditions Summary Saturday, Feb. 10 – Sunday, Feb. 11 Bottom Line: A storm impacting Summit will produce strong winds and up to 6" of new snow making it likely to trigger a wind slab avalanche up to 1' to 2' deep. It is also possible that storm snow and wind slabs may stress a buried weak layer enough to produce deeper and larger avalanches at all elevations, including lower elevation terrain. During stormy weather we recommend avoiding steep wind loaded features and avalanche terrain in general. Special Announcements The Chugach National Forest Avalanche Center has issued an avalanche warning through the National Weather Service for Girdwood, Portage, Turnagain Pass, Moose Pass, and Seward that will end at 9pm Saturday, February 10. The National Weather Service has issued a winter weather advisory for Turnagain Pass through 9pm on Friday, February 9th 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. Conditions Recent Avalanches: A natural avalanche was reported today (Feb 9) on Templeton Mtn. It is possible the avalanche released last night due to high winds transporting fresh snow. Otherwise, the last reported avalanche was a wind slab avalanche on Tributary Mtn on Jan 30. The slab was around a foot deep and about 80ft wide. That being said, visibility in Summit earlier this week has made it difficult to see avalanche activity. Weather Recap: Last weekend around 5" of new snow fell accompanied with northeast winds gusting to 30 mph. From Tuesday into Wednesday Summit Pass was mostly cloudy and windy with ridgetop winds averaging 20 to 30 mph and temperature increasing from single digits to low 30’s F. A storm arrived on Thursday afternoon bringing 1" of snow overnight, northeast winds gusting to 60+ mph and above freezing temperatures in the pass. Friday delivered 35 mph gusts by the highway, 50+ mph on ridgetops, a few inches of snow, and above freezing temperatures (35 F). Weather Forecast: The storm that arrived on Thursday is forecast to bring cloudy skies and up to 6" of new snow to Summit over the weekend with strong winds. On Friday night into Saturday morning sustained winds 20 to 30 mph from the southeast are expected with 40+ mph ridgetop winds, a few inches of new snow, and temperatures dropping to the mid 20’s F. Saturday is likely to receive another few inches of snow and sustained southerly winds averaging 15 to 25 mph with ridgetops gusts 30 to 40 mph and temperatures averaging 20 to 30 F. On Sunday the sun may shine through cloudy skies as the storm begins to break up with ridgetops winds from the south averaging 10 to 20 mph, 30+ mph gusts a few lingering flurries and temperatures averaging 15 to 25 F. Avalanche Problem 1 - Wind Slabs Strong winds are forecast out of the east on Friday night then switching out of the south on Saturday which will cause wind slabs to form on multiple aspects. These winds are expected to transport new and old snow into touchy wind slabs 1 to 2' deep at all elevations that is affected by the wind including below treeline. Wind slabs can be found on the leeward side of wind affected features such as below ridgelines, convex rollovers, and in cross loaded gullies. Red flags such as natural avalanches, blowing snow, and shooting cracks indicate that you can trigger an avalanche. The safest option is to avoid steep wind loaded slopes instead riding lower angle terrain not affected by the wind until the snowpack has had time to settle. It is possible that fresh wind slabs will also be forming over a persistent weak layer buried 1' deep that will increase the likelihood of triggering a much larger avalanche. More about this in our problem 2. The Alaska Railroad at Mile 43 Peak weather station records wind patterns similar to Summit’s ridgetop winds. This wind rose is showing very strong winds from the east northeast. Avalanche Problem 2 - Persistent Slabs The weak sugary snow and surface hoar that formed during January’s period of cold clear weather is now covered by 1' of snow. This weekend’s strong winds and new snow will add stress to this layer however, it may not be enough to cause natural avalanches. If that is the case then this layer may not show signs of instability until it is triggered. It has been observed from the highway to 2500' making it a widespread issue including areas below treeline that has been relatively safe for most of the season. We recommend staying out of avalanche terrain (30 degree slopes or steeper) until the storm subsides and we get a better idea as to how sensitive the layer is. It is also important to mention that while red flags such as cracking, collapsing, and recent avalanches can provide some information, persistent slabs may not give you any clues until they avalanche. Additional Concern Glide Avalanches It has been over two weeks since a glide avalanche was reported in Summit Pass. As always try to avoid traveling under these glide cracks because it is possible for new or old cracks to release into an avalanche. US Forest Service Turnagain Pass Avalanche Advisory ARCHIVED - Forecasts expire after 24 hours. Issued: Tue, February 13th, 2024 - 7:00AM Expires: Wed, February 14th, 2024 - 7:00AM Forecaster: Wendy Wagner High Avalanche Danger - Travel in avalanche terrain is not recommended. Avoid being on or beneath all steep slopes. The Bottom Line Very strong east winds are impacting the mountains and raising the avalanche danger to HIGH at the mid and upper elevations. Naturally occurring wind slab avalanches are likely and human triggered avalanches are very likely on any wind loaded slope. Travel in avalanche terrain is not recommended during this stormy and windy weather, including runout zones under large avalanche paths. Although it’s raining below 1,000', the danger is CONSIDERABLE in avalanche paths due to avalanches that may occur above. ROOF AVALANCHES: Watch for snow to continue to slide off roofs due to rain and warm temperatures. Special Announcements Chugach State Park: Dangerous avalanche conditions exist due to very strong easterly winds. A large natural avalanche occurred in the South Fork of Eagle River yesterday that deposited up to 7 feet of debris onto the Hiland Road around mile 7. No people, cars, or structures were reported to be involved. The CSP Avy Specialist happened to be in the area at the time and was able to get some photos and information. The National Weather Service has issued a High Wind Watch for the Anchorage’s Front Range, in effect until 9pm tonight. Forecast - Tue, February 13th, 2024 Danger Level: 4 - High at and above treeline (1000'); 3 - Considerable below treeline Recent Avalanches We are unaware of any confirmed natural or human triggered avalanches in our forecast area from yesterday. That said, behind the clouds there were probably several natural wind slabs that released due to the sustained strong east winds. We did get reports of collapsing in the snowpack in the mid elevations on Center Ridge and Tincan. Avalanche Problem 1 - Wind Slabs Likelihood: Very Likely Size: Large (D2) to Very Large (D3) If you thought the winds were strong yesterday, wait for today. This weather event is producing significantly strong easterly winds region-wide with not a lot of snow, interestingly enough. Snowfall over the past 36 hours has added up to 4-8" at Turnagain and 6-10" in Girdwood, another 1-3" is expected today. Sustained winds along the ridgetops are currently 25-40 mph with gusts between 50 and 90 mph. The peak in wind is expected midday today. That means even stronger winds could develop. Either way, the wind is by far the major contributor to the increase in avalanche danger. Sunburst (Turnagain ): Max gust 83 mph Max’s Mtn (Girdwood): Max gust 87 mph Wind Slab Avalanches: Naturally occurring wind slab avalanches are likely happening now and should continue through the day. These slabs could be several feet deep, break in older weak layers making the avalanche larger, and run further than expected. Also note, winds could be getting into the mid elevations and loading slopes that don’t usually see wind loading. It’s one of those days that the weather will most likely keep many of us out of the mountains or in sheltered areas outside of avalanche terrain. This is the best bet for today. Cornices: The warm(ish) temperatures and strong winds are likely forming new cornices and these are likely breaking off in pieces. This is a typical way wind slabs are triggered, from a piece of cornice falling onto a wind loaded slope. Avalanche Problem 2 - Persistent Slabs Likelihood: Likely Size: Large (D2) to Very Large (D3) Buried anywhere from 1 to 3 feet deep at this point is that old layer of sugary faceted snow that formed in January. This layer exists everywhere, but is variable as to how weak and concerning it is. It has shown to be the weakest at elevations between 1,000 and 2,000 feet. This is right in the treeline band where a lot of traffic can take place. Hence, the places we might seek out during windy weather could also produce an avalanche. Hopefully we’ll get to see some of the aftermath of what kind of avalanches the winds were able to make. Until then, sticking to low angles well out of any avalanche path above is recommended. Additional Concern - Glide Avalanches Glide avalanches are still a concern on any slope with glide cracks present. We have not seen or heard of one releasing into an avalanche for over two weeks now, but that doesn’t mean a crack can’t release today. Continuing to avoid time under glide cracks is prudent.