Blue skies and warm days will continue to be the theme for today and into the workweek. As the mountains continue to heat up a bit more each day, they will become more and more dangerous. It is important to pay close attention to how the warming is affecting the pack. We are in a melt-freeze cycle on Southerly slopes – hard frozen crusts in the morning, which turn to unsupportable mushy and unstable snow by the afternoon/evening. Each night the re-freeze is a bit less and the melt phase is a bit longer, creating a longer period of heightened avalanche conditions. Choosing what aspect to travel on, paying attention to the time of day and how long the slope you are on has been exposed to direct sunlight are essential to staying out of trouble.
Over the past few days many natural wet avalanches have occured. The activity looks to be starting around 12:00 pm and continuing into the evening hours, as late as 8 or 9pm. Natural avalanches were witnessed on the front and backside of Seattle Ridge, in Girdwood, in Placer and in Whittier on Friday. In the Lost Lake area several wet avalanches have been seen this past week. A large skier triggered avalanche occurred on Sunburst on Thursday on a Southerly slope. Zones with thin snowpacks have been particularly active where free water is interacting with old weak snow. Wet loose snow avalanches may also trigger deeper slabs.
If heading out for a fun day in the sun keep these points in mind:
Large wet slabs on the Southwest face of Cornbiscuit – released sometime over the weekend (4/15 or 4/16). Mike Davidson Photo.
Natural avalanche that occured Friday around 5:30 pm on Ragged Top mountain in Girdwood Valley, Southeast facing slope.
Natural wet slab avalanche in the Lost Lake and Snug Harbor zone from earlier in the week (Photo: Troy Tempel). This areas is out of our forecast zone, but it is the type of avalanche activity we have been seeing on Southerly aspects – including the Seattle Creek drainage.
On the shaded and cool side of the mountains (Northerly aspects) dry snow still exists. There are several weak layers anywhere from 2-5′ below the surface. As folks venture out looking for “cold snow” this remains a concern. Shaded aspects (NE – NW – W) in the mid and upper elevations that haven’t avalanched already are the most suspect places for triggering a deep slab.
This problem is one of low probability but high consequence as these are large and potentially unsurvivable slides. As the snowpack continues to adjust, triggering will become more stubborn and less likely with time. Keep these point in mind:
Several small glide avalanches have released on Southeast facing Seattle Ridge and Eddies Ridge over the past few days. We expect this trend to continue with the warm days ahead. Keep an eye out for glide cracks, full depth cracks in the snow, and limit time underneath them.
Cornices: Cornices are large and likely hanging close to their tipping point. Direct sunshine, a person, or a group of people on top these could be enough to cause one to break. An observer in Seattle Creek noted a large cornice fall on Friday. Cornice crevasses have also been noted (opening slots where the cornice is pulling away from the ridge but has not broken off. Give cornices a wide berth from above and limit exposure under them from below.
Glide avalanches and glide cracks near the Seattle Ridge up-track.
Over the past 24-hours skies have been clear and winds have been light along the ridgetops, in the 0-10mph range from an Easterly direction. Temperatures were a bit cooler than yesterday, but are still warm, climbing from the 20’s to the 50’s at sea level and rising to the mid 30’sF along the ridgelines.
Today and Monday, we can expect very similar weather – bluebird. Winds should remain light from an Easterly direction and calm at times. Temperatures are expected to rise to the 50’sF at elevations below 2,000′ and into the 30’s and 40F along the ridgetops.
This stretch of high pressure and clear sky days should extend into the coming workweek.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||40||0||0||66|
|Summit Lake (1400′)||38||0||0||22|
|Alyeska Mid (1700′)||41||0||0||61|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||No Data||SE||7||15|
|05/06/20||Turnagain||Avalanche: Pastoral Peak, north face||Andy Duenow|
|04/10/20||Turnagain||Avalanche: Wolverine||Mike Records|
|04/10/20||Turnagain||Observation: Eddies lookers right shoulder||Matt Yoder|
|04/09/20||Turnagain||Observation: Bench Peak||Mike Records|
|04/04/20||Turnagain||Observation: Pete’s North||Anonymous|
|03/26/20||Turnagain||Avalanche: Tincan – Proper (SW facing)||CNFAIC Staff|
|03/26/20||Turnagain||Avalanche: Seattle Ridge||W Wagner Forecaster|
|03/25/20||Turnagain||Avalanche: Sunburst Uptrack @ 2000′||J. Boisvert|
|03/24/20||Turnagain||Observation: Turnagain – Road Observations||W Wagner Forecaster|
Status of riding areas across the Chugach NF is managed by the Glacier and Seward Ranger Districts, not avalanche center staff. Riding area information is posted as a public service to our users and updated based on snow depth and snow density to prevent resource damage at trailhead locations. Riding area questions contact: firstname.lastname@example.org
|Area||Status||Weather & Riding Conditions|
This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area. This advisory does not apply to highways, railroads or operating ski areas.