|Signal Word||Size (D scale)||Simple Descriptor|
|Small||1||Unlikely to bury a person|
|Large||2||Can bury a person|
|Very Large||3||Can destroy a house|
|Historic||4 & 5||Can destroy part or all of a village|
One more sunny day is on tap as our brilliant 11-day stretch of warm springtime weather comes to a close. The high pressure ridge that has been over Southcentral is beginning to break down. Although clear skies remain today, we should see slightly cooler temperatures and an easterly breeze along ridgelines (5-10mph). Tomorrow, Wednesday, cloud cover is forecast to head in with increasing east winds and even cooler temperatures. What this all means avalanche-wise is delayed to limited softening of surface crusts, which equals decreasing avalanche danger. Other than the unpredictable glide avalanche, the rest of our avalanche concerns are directly related to the amount of daytime heating and melting of the crusts.
The big question to answer will be, how mushy is the surface getting? Yesterday, temperatures were a bit cooler than the weekend and surfaces took an hour or two longer to soften (See Nick’s Sunday report compared with George’s report from Monday). Today and tomorrow we are expecting to continue that trend of delayed warming. With the cooler conditions, we are not expecting to see natural avalanches. However, there should be enough warming today for folks to find fun corn followed by the chance slopes get warm and saturated enough that human triggered wet avalanches become possible.
Wet Loose avalanches: Human triggered wet sluffs (or push-a-lanches) will become possible on any slope around 35 degrees or steeper that has punchy, boot-top wet slushy snow. These types of wet sluffs can be easy to identify if we are looking out for them. They could be fairly small and not a big deal, or if the terrain is steep enough, generate a large amount of mass and become quite destructive and dangerous. It’s always best not to mess around with these and once the snow starts to push easily down a slope, it’s time to move to an aspect with less warming.
Wet Slab avalanches: It remains possible to trigger a wet slab on slopes seeing significant warming, similar to wet sluffs. Wet slab avalanches occur when water penetrates and lubricates a deeper layer in snowpack. The water causes that layer to lose its strength and the snow above fails and avalanches. Wet slabs are often triggered by a wet loose avalanche and are most likely to occur in areas with a thinner snowpack, such as Summit Lake.
Cornices: The past many days of warm temperatures is causing looming cornices to slowly droop. These are most unstable in the heat of the day, but should be suspect anytime really. Remember, a cornice fall could trigger a wet avalanche on the slope below when conditions are ripe. Be aware to not accidentally travel onto one and limit any exposure under them.
Cornices along the Magnum Ridge. 4.26.21. George Creighton.
Tincan seen from the air by Aleph on Saturday. There is still a lot of snow and fun to be had at Turnagain Pass! 2.24.21.
Glide cracks continue to open up around the region. This includes areas that are commonly traveled, such as Seattle Ridge and Tincan. Keep an eye out for the ‘brown frowns’ on the mountainsides and be sure to avoid and/or limit any time under them. Glide cracks are extremely unpredictable and can avalanche at anytime – including during colder weather and when surfaces are frozen.
Glide cracks and two older glide avalanches seen on the front (road) side of Seattle Ridge. 4.26.21. George Creighton.
Older glide avalanche on the southern side of Tincan Ridge. 4.26.21. George Creighton.
Yesterday: Sunny skies with light easterly ridgetop winds (5-10mph) were over the region. Temperatures rose from near 30F in valley bottoms to 55+F through the day, while ridgetops climbed from ~35-40F to the mid 40’sF.
Today: One last full sunny day is expected today as the high pressure ridge over us breaks down to allow for moisture to move in later this week. Temperatures look to be a hair cooler today with high’s near 40F along ridgetops and in the 50’sF in valley bottoms. Ridgetop winds should remain light from the east, 5-10mph.
Tomorrow: Clouds are forecast to begin moving over the the region tomorrow afternoon with a chance for a little rain/snow on Thursday. Ridgetop winds will remain easterly tomorrow and increase into the 10-20mph range. Temperatures should stay on the cooler side with highs along the ridgelines in the mid 30’sF and mid 40’s in valley bottoms. It’s looking like a chance snow could fall as low as 1,000′ this weekend as a more active and moist weather pattern sets in.
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||41||0||0||91|
|Summit Lake (1400′)||42||0||0||29|
|Alyeska Mid (1700′)||43||0||0||102|
RIDGETOP 24-hour data (6am – 6am)
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||40||SE||7||15|
|04/30/21||Turnagain||Observation: Sunburst||W Wagner Forecaster|
|04/27/21||Turnagain||Observation: Tincan Ridge||Joe Kurtak|
|04/26/21||Turnagain||Observation: Magnum||Creighton/ Hoople|
|04/25/21||Turnagain||Observation: Sunburst||Nick D'Alessio|
|04/24/21||Turnagain||Observation: Airplane obs||Johnston-Bloom / DiJulia /Hilliard Forecaster|
|04/24/21||Turnagain||Observation: Corn biscuit||Heather Johnson|
|04/23/21||Turnagain||Avalanche: Lynx Ck Drainage||W Wagner Forecaster|
|04/23/21||Turnagain||Avalanche: Sunburst||Eeva Latosuo|
|04/23/21||Turnagain||Observation: Center Ridge Turnagain pass||Joe Kurtak|
|04/22/21||Turnagain||Observation: Turnagain Seattle Ridge / Seattle Creek||Troy Tempel|
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.