Another warm, wet and windy storm is impacting the Eastern Turnagain Arm region once again. This system moved in yesterday afternoon and will be exiting today. So far we have seen just under an inch of rain up to 2,500′ with heavy wet snow above this. The rain has likely melted most surface crusts up to 2,500′, and possibly higher, and will continue to saturate the snowpack. This will create wet loose avalanche potential along with an increased glide avalanche potential.
Since the pack has already adjusted to rain up to 2,500′ from the last storm, it is not prime to produce significant natural wet avalanche activity. Yet, at the upper elevaitons we may see some shallow wet loose avalanches in the new snow as temperature climb slightly today. That said, human triggered wet loose snow avalanche will be possible on steep slopes where loose, unconsolidated and soggy snow exists. On sustained steep slopes these could be quite large. Avoiding steep terrain with unsupportable wet snow is recommended.
We are currently in a “glide cycle” of sorts. We have seen widespread glide crack development through Turnagain Pass and Girdwood Valley during the past 3 days. Only a handful of these cracks have actually avalanched. Check out the comparison photo below put together by Heather Thamm. This shows that not all glide avalanches are preceded by a slowly opening crack. Something to keep in mind if you are headed out in the backcountry. This can make avoiding being under a glide avalanche more tricky, but most of the time they do have glide cracks present which are easy to recognize.
While it has been raining up to 2,500′, it has been snowing above this. I think it is safe to say that around 5-8″ of heavy to medium density snow exists and covers essentially the top 500-1,000′ or so of the ridgelines around Turnagain Pass. The new snow has come in with strong Easterly winds which has likely built wind slabs up to 8-16″ in depth. Another 2-4″ of snow is expected with moderate Easterly winds today which, if this is the case, add to the slabs from the past 24-hours. These will be sitting on a hard pre-existing crust and bonding of the new slabs to the older crust is uncertain. However, I’d expect with the warm temperatures, that these slabs should settle out rather quickly and be somewhat stubborn to trigger.
If you are headed out in search of new snow at the high elevations, watching for red flags (recent avalanches, collapsing and cracking in the new snow) will be essential. Quick hand pits are an additional great way to see how the new snow is bonding.
Light rain spread over our area yesterday with a more intense precipitation period overnight as a warm storm is slowly exiting the region. A total of 0.9″ of water has accumulated at the Center Ridge Snotel station as of this morning while Girdwood Valley has seen 0.7″ and Summit Lake recording no measureable precipitation. The rain/snow line was up to 2,500′ with temperatures close to 30F on the ridgetops and the upper 30’s F below treeline. Winds have been strong from the East, averaging 33mph with gusts over 70mph at the Sunburst weather station.
Today, 0.3-0.5″ of rain is expected to continue up to 2,500′, possibly higher, with 2-4″ of heavy snow above this. Temperatures should remain near 30F on the ridgetops and in the upper 30’s at and below treeline. Ridgetop winds will continue from an Easterly direction in the 20-25mph range.
As we head into the remainder of the week, a series of warm low pressure systems continue to spin in the Gulf bringing intermittent rain showers. The rain/snow line looks to remain near 2,500′ (or higher) through Thursday. Friday, cooler air does look to become mixed in and we may see the rain/snow line drop to 1,500′ or so for the weekend.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||36||0||0.9||29|
|Summit Lake (1400′)||37||0||0||5|
|Alyeska Mid (1700′)||36||0||0.7||21.5|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||30||NE||14||42|
|04/19/21||Turnagain||Avalanche: Triangle, Seattle creek||Will Morrison|
|04/18/21||Turnagain||Avalanche: Turnagain Pass Road Obs||Andy Moderow|
|04/18/21||Turnagain||Observation: Seattle Ridge, approximately 300 yards south of the up track||Brent Byrne|
|04/17/21||Turnagain||Avalanche: Road obs||Johnston-Bloom / Moderow Forecaster|
|04/16/21||Turnagain||Avalanche: Seattle Ridge||Wendy Wagner Forecaster|
|04/16/21||Turnagain||Avalanche: Turnagain Pass, non-motorized side seen from Seattle Ridge||CNFAIC Staff Forecaster|
|04/16/21||Turnagain||Observation: Sunburst||Lance breeding|
|04/15/21||Turnagain||Observation: Tincan||Schauer/ Rothman Forecaster|
|04/13/21||Turnagain||Observation: Turnagain Pass Road Obs||A Schauer Forecaster|
|04/12/21||Turnagain||Observation: Tincan||Johnston-Bloom / Latosuo 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: email@example.com
|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.