As has been the theme for December, another warm storm is on the doorstep. This one will be arriving today. Winds have already picked up from the East and after a pulse of heavy precipitation for a few hours overnight, light precipitation is expected today before ramping back up tonight. I hate to say it, but the warmest temperatures we have seen so far have occurred during the past 24 hours. This has bumped the rain/snow line up to 2,600′ and possibly created some wet avalanche activity – more on that below.
Avalanche conditions: Dangerous. The weak faceted snow that sits underneath the past 2 weeks of storm snow continues to prove itself reactive. Although this layer is slowly becoming more and more buried (20″-4+’ below the surface) and showing signs of being slightly more stubborn to trigger – it remains our primary concern. Future avalanches triggered, either by the upcoming storm(s) or a person, are becoming larger and could allow a person/people on to them before releasing. Keep in mind slopes that have already avalanched could reload and release again.
This storm’s new snow and wind at the high elevations will be creating another set of avalanches problems including wind slabs, storm slabs and cornice falls. All these storm snow issues will likely be hard to see in the clouds today, however, even small avalanches due to the storm have the potential to trigger a larger slab breaking in the weak facets near the ground.
If you are headed out to the mountains today, we recommend staying off slopes steeper than 30 degrees with nothing steeper above you, be careful to avoid runout zones and bring your rain coat.
If you look closely, you can see a streak of debris down Todd’s Run on the North side of Tincan. This avalanche occurred sometime on Thursday, Dec 7th.
Natural slab avalanche occured sometime between Friday night and Saturday (Dec 8-9) in steep terrain on Seattle Ridge – photo Joe Kurtak.
Pictured below is Seattle Ridge and the common motorized up-track as seen from Tincan. This slope, along with many other in the Turnagain area, has not avalanched and suspect to do so. Remeber, weak layers are guilty until proven innocent.
Rain falling up to, and possibly higher, than 2,600′ will be falling on snow. This is a text book case for creating wet avalanches in the elevation band of 1,000′ – 2,600′ and possibly higher. Little to no snow sits below 1,000′ and therefore the hazard there is due to avalanches releasing above sending debris into this zone. Not only wet loose slides are expected, but wet slab avalanches could occur today and through tomorrow with these very warm temperatures.
Yesterday, overcast skies and light precipitation were over the region. A pulse of heavy rain (~ 0.5″) occurred below 2,500′ overnight with an estimated 5-7″ at the higher elevations. A 24-hour total of precipitation was 1″ of rain in the Girdwood Valley and slightly less at Turnagain Pass with roughly 6 – 12″ of snow in the Alpine above 2,500′. Temperatures as you can expect with this high rain line, were warm – climbing up to 33F at 3,800′...! Winds were light yesterday and have increased overnight with averages in the 20-30’s mph with gusts up to the 60’s from a generally Easterly direction.
Today, another shot of rain, snow and wind is arriving. Winds have climbed as mentioned overnight and are expected to remain strong today through tomorrow. Ridgetops should see averages in the 20-30’s mph from the East with gusts up to 70mph or more. Precip amounts will be moderate through the day and significant tonight with a rain/snow line around 2,600-2,800′. Around .5″ rain expected today (5-7″ snow in Alpine) and 1″ tonight (10-12″ snow in Alpine).
*There is ‘High Wind Watch’ issued by the NWS tonight through tomorrow morning for Portage Valley and Turnagain Arm.
The longer term forecast continues with an active pattern, yet cooler temperatures should arrive Monday for a brief period, before a more significant cooiling trend is expected Wednesday through Friday. This means a lowering of the rain/snow line, cross you fingers!
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||37||0 (rain)||0.7||23|
|Summit Lake (1400′)||36||0 (rain)||0.2||10|
|Alyeska Mid (1700′)||36||0 (rain)||1.07||18|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||33||SE||19||59|
|12/08/19||Turnagain||Avalanche: Tincan||Ryan Van Luit Forecaster|
|12/06/19||Turnagain||Avalanche: Sunburst||Billy Finley|
|12/04/19||Turnagain||Observation: Sunburst||A.Johnston-Bloom/ W.Wagner/ R.Van Luit Forecaster|
|12/03/19||Turnagain||Observation: Hippy Bowl||Nick Langowski|
|12/01/19||Turnagain||Observation: Tincan, All elevations||Eric Roberts|
|12/01/19||Turnagain||Observation: Tincan||Andy Moderow|
|11/30/19||Turnagain||Observation: Tincan Treeline Plateau/ Common Bowl/ Ridge||Eric Roberts|
|11/29/19||Turnagain||Observation: Sunburst Ob #2||Aleph Johnston-Bloom Forecaster|
|11/29/19||Turnagain||Observation: Sunburst Ob #1||Aleph Johnston-Bloom Forecaster|
|11/27/19||Turnagain||Observation: Tincan||Aleph Johnston-Bloom 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|
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