Yep, we are finally getting our warm April temperatures and a little rain and snow today. We only have a small amount of precipitation forecast but, the main concern is how the snowpack is reacting to the warm temperatures and cloud cover. Below treeline, watch for the top 6-12+” of snow to lose cohesion and be easily pushed down any slope over 35 degrees. Mainly wet loose avalanches will be possible to trigger but there is also a potential for wet slabs around a foot deep to pull out. It is best to steer clear of any slope with soft wet snow deeper than 6″. Additionally, buried crusts in many areas can provide great bed surfaces allowing any slide triggered to run further than expected.
As for the larger and more dangerous slides: Once the entire pack warms up to a balmy 32F (0C) we call it isothermal and it looses much of its stability. This is the primary contributor to the shed cycle. Right now the snowpack at 2,000′ is not quite warm enough (see image below). However, snow can change rapidly and with that the avalanche danger. You can keep tabs on the evolution of the snowpack HERE but also keep in mind this is only one point (2,000′ on Center Ridge) and the snowpack varies considerably with elevation and aspect.
Above treeline we can expect several inches of heavy snow today with moderate to strong east winds. The new snow is likely to stick rather well to the existing surface at the mid elevations but upper elevations should see dryer snow with more of a classic winter wind slab problem. Expect any fresh slab found at these upper elevations to be sensitive as they will be sitting on either crusts (wind or sun) or loose faceted snow.
Cornices are likely to start peeling off any day now with our recent warm temperatures. They have the potential to trigger avalanches below, entrain large amounts of snow and run into valley bottoms. Again, with the springtime warm-up on the way, be very wary of traveling in drainage bottoms for the next several weeks.
Yesterday we had a brief return to the sunny skies that have characterized April to date. Temperatures were quite warm, around 30F on ridgetops and the upper 40’s at 1,000ft. Ridgetop winds during the past 24 hours averaged ~15mph with gusts to 35mph from the east. The last snowfall ended 13 days ago, April 9th. Overnight, cloud cover has moved in and temperatures have only dropped 5-10F – it’s feeling like spring finally.
Today a warm, wet and windy, but fast moving, system is moving through from the Gulf. We should see around 4-6″ of dense snow above treeline and .3″ of rain below treeline throughout the day (rain/snow line ~1,500ft). Temperatures look to rise back to 30F on ridgetops and the mid 40’s at 1,000ft. Winds will remain from the east in the 15-20mph range with gusts to ~40mph.
Wednesday we should see partly cloudy skies as the system moves out and we return to a dry, but warm, period for the remainder of the week.
Kevin will issue the next advisory Thursday morning, April 25th.
|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.