It’s official – after a two-week dry spell, snow is falling this morning!! Although there’s only been around an inch so far, by this evening we could get up to 8-10″ in favored locations and 4-6″ in un-favored locations. Plus, an additional 4-6″ is possible overnight tonight. It will be one of those days to keep close tabs on how much new snow has fallen and how hard is it snowing. This will directly influence the avalanche hazard. The new snow is falling on a variety of old surfaces, including slick hard wind slabs/crust and soft faceted snow. Despite the myriad of different surfaces, expect bonding of the new snow to initially be poor.
Upper-elevation slopes in the Alpine are likely to be obscured today, but this is the terrain most suspect for receiving enough snow (up to 8+”) along with winds strong enough to form wind slabs that release naturally. If you find yourself in this situation, expert level snowpack assessment is necessary for entering avalanche terrain. Mid-elevation slopes and areas in the trees are more likely to receive less snow (4-6″) and little wind. In this terrain, naturally occurring avalanches are unlikely but human triggered shallow soft slabs and sluffs, the depth of the new snow, may be possible on the steeper slopes.
What to watch for:
Stepping off the skin track or jumping off your snowmachine to do quick hand pits will be a great tool for sussing out new snow depth and bonding. If skies are clear enough, look for loose snow avalanches in the steep terrain and keep your situational awareness up as the day progresses!
Photo below: An example of the pre-existing snow surface that the new snow is falling on – old hard wind slabs/crusts. Very weak faceted snow sits under these hard slabs and crusts. Once the storm snow bonds with the crust we could see avalanches breaking in the faceted snow beneath (will we get enough of a load for this? a focused question for this weekend).
Warming temperatures associated with the Southerly flow may enhance glide activity. Glide cracks have been slowing opening this week; though we have not seen/heard of any new cracks releasing. Keep an eye out for cracks, which is difficult with new snow and wind, and limit time underneath them.
Yesterday was our last clear sky day with temperatures in the single digits in valley bottoms and the teens-20’s in the upper elevations. Ridgetop winds picked up later in the day from the Southeast to the 10mph range.
Overnight, clouds filled in and light snowfall began around 3-4am. Roughly a trace to an inch is being reported at stations this morning, including snow to sea level. Ridgetop winds have bumped up to 15-20mph with gusts into the 30’s. Temperatures have climbed dramatically at sea level as the inversion has been scoured away (28-30F at sea level, mid-20’s at the mid-elevations and mid-teens at the Ridgetops).
Today, we are expecting anywhere from 4-8+” of new snow and another 4-6″ tonight. Although temperatures have warmed dramatically, we should still see mostly snow to sea level with this event. Ridgetop temperatures will be in the mid-20’s F. Ridgetop winds are likely to increase more today into the 20-40mph range with gusts into the 50’s.
Tomorrow the system looks to move out and skies begin to break up as a cold and dryer North flow heads our way.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||21||trace||0||33|
|Summit Lake (1400′)||10||0||0||11|
|Alyeska Mid (1700′)||20||0.3||0.1||21|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||17||SE||17||35|
|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: 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.