After a nearly two week dry spell, the mountains finally had a fresh dusting of snow in most areas yesterday. Yesterday was a teaser however with only 2-4″ of very low density snow accumulating. Today, on the other hand, will hopefully be enough of a re-fresh to cover the plethora of old tracks littering the mountainsides. From this morning through tonight the National Weather service is calling for 5-9″ of low density snow. They also have a Winter Weather Advisory is in effect.
That all said, if the snowfall forecast verifies, along with the increase in wind; ridgetop winds due to pick up to 15-20mph from the North and West. We are sure to see several shallow wind slabs, soft slabs and loose snow avalanches. The new snow from yesterday and today is falling on a very weak surface of both near surface facets and surface hoar. It will not take much wind and new snow to create very touchy wind slabs. Due to the small amounts of new snow, these slab should fairly shallow – up to a foot thick, but prevalent.
What to watch for and keep in mind for today:
Surface conditions before the new snow: Surface hoar – this is now buried by 3-4″ of new snow from yesterday, with more today.
Unfortunately, we continue to find weak snow near the ground in the region (faceted snow and depth hoar). This is in a variety of layers all found in the bottom 2 feet of the snowpack. Areas with a thicker pack, such as the core slopes around Turnagain Pass, the weak snow is much stronger. But, just 5 miles down the road the pack is shallower and the weak snow is impressively weaker (as can be seen in the video below). After almost two weeks of quiet weather, these weak layers have become harder and harder to trigger as the pack has mostly adjusted. However, though the probability of triggering a deep slab avalanche is low, the consequences are high – as we have been saying for a while now. Keep that in mind along with sticking with safe travel practices.
The new snow we are getting out of the system over us now is not adding much load (only around .5 to maybe 1″ of water equivalent). However, next week’s warm stormy weather could be enough to re-active these old layers creating large dangerous avalanches. We will see.
Light snowfall covered the area yesterday adding 2-4″ of very low density snow. Skies were mostly overcast with a few ‘sucker holes’ of blue sky in the afternoon. Ridgetop winds were breeze from a North and Westerly direction (5-10mph). Temperatures were in the 15-20F range in parking lots (relatively warm) and cooling down on the ridgelines to the 10-15F range.
Today, we should see light snowfall kick up again, with another 5-9″ of low density snow accumulating by tonight – possibly more in favored areas. Ridgetop winds are expected to bump up to the 15-20mph range from the North and West. Gap winds along Turnagain Arm at sea level should be strong. Temperatures are decreasing as this cold Northerly flow pushes through – single digit temperatures are seen in valley bottoms to ridgelines with sea level zones in the mid-teensF.
The cold low-pressure system impacting us today will move out tonight and clearing skies and cold temperatures are expected for Saturday into Sunday. Sunday night into next week looks interesing – as the National Weather Service states:
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||13||3||0.2||52|
|Summit Lake (1400′)||15||2||0.1||25|
|Alyeska Mid (1700′)||14||2||0.1||48|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||10||N||5||11|
|04/21/21||Turnagain||Observation: Sunburst||Schauer/ Behney Forecaster|
|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|
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.