Today is a transition day. We have had mostly cold clear weather with no precipitation for the last few days. This afternoon the winds are forecasted to pick up and snow should start falling. The new snow will be falling on very weak surface snow. There is widespread surface hoar, with near-surface facets below or hard wind crust or firm melt-freeze crust. None of these old snow surfaces bode well for snow bonding to them. As the weather comes in today it will be important to pay attention to changing conditions. Slabs may form quickly, especially in leeward terrain. Quick hand pits can help check if the new snow is sticking to the old snow surfaces or not. The weak surface snow can also act as a few inches of fast moving loose surface snow “sluff” that could catch you by surprise if you’re not expecting it in steep terrain.
In addition, as you are out recreating today keep in mind triggering an old wind slab is still possible on very steep terrain in the alpine zone. Places you might find a hard wind slab will be in steep couloirs, large unsupported terrain features, or in thin rocky areas. Triggering a wind slab in the Treeline zone is becoming less likely, but is not out of the question in high consequence terrain. Triggering a wind slab could take you for an undesirable ride, and has the potential for initiating a much larger and more dangerous avalanche above 3000′. Be suspect of any slopes that may harbor a deep slab problem in the upper elevations.
Surface hoar over near surface faceted snow over a melt freeze crust on Seattle Ridge.
It has been over a week since a large avalanche was triggered on Pastoral by two skiers traveling below the NW face. If you have been reading the forecast regularly we are not trying sound like a broken record but the message is the same. This snow pack set-up continues to warrant elevated caution and respect. It is a high consequence avalanche problem that is impossible to outsmart and can take a long time to heal. The ingredients for a deep slab avalanche have been found in the upper elevations of our forecast zone, above 3000’ on slopes that did not avalanche in the early December storm cycle. This is a hard slab, 3-5+ feet thick, sitting on top of weak sugary snow (basal facets) near the ground. Observations over the last few weeks indicate this poor structure is widespread across our region in the alpine elevations. As the load increases over this snowpack structure during the upcoming storms there will be the potential for large natural avalanches.
When dealing with a deep slab avalanche problem, keep in mind:
Yesterday was overcast with temperatures in the teens and low 20Fs. Winds were easterly 5-15 with gusts into the 20s. Overnight the temperatures rose a little.
Today will be mostly cloudy with a chance of snow showers in the morning and snow likely in the afternoon. 1-5″ during the day. Winds will be easterly building this afternoon into the evening, 10-20 mph with gusts into the 30s and 40s. Temperatures will be in the 20Fs.
Tonight the snow is forecasted to be heavy at times, 6-12″. Easterly winds could into gust into the 60s. Temperatures stay in the 20Fs. There is a Winter Storm Watch in effect.
Tomorrow will be cloudy with snow likely and heavy at times, 7-10″. Winds will be 10-20 mph with gusts into the 30s. Temperatures will slowly rise with a potential for some “mixed” precipitation at lower elevations. The storm will continue into the New Year. The pattern is very active this week with another system on track for Tuesday. Stay tuned!
The National Weather Service is forecasting 2’+ for Turnagain Pass by Monday.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||20||0||0||30|
|Summit Lake (1400′)||17||0||0||12|
|Alyeska Mid (1700′)||21||0||0||26|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||17||E||15||28|
|04/18/21||Turnagain||Avalanche: Turnagain Pass Road Obs||Andy Moderow|
|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|
|04/10/21||Turnagain||Observation: north sides||lance breeding|
|04/09/21||Turnagain||Observation: Girdwood to 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: 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.