Turnagain Pass Avalanche Forecast

Today looks to be the classic “Day after the storm” day.  Storm totals were in the 1 foot range at mid-elevations with snow falling down to sea level.  The winds, though potent at the beginning of the storm lessened around noon yesterday.  As we are still within the 24-hour window directly after a storm, expect this most recent layer of storm snow to be touchy today, particularly in steeper terrain.  Very little information is known above treeline as to how well storm snow is bonding given difficult travel yesterday, but we can assume tender wind slabs at higher elevations, chiefly below ridges and on west facing (leeward) slopes.  These wind slabs may be covered up with a fresh coat of white given the lack of wind during the latter half of the storm. 

Storm snow at around 1000’ did exhibit an upside down character and several point releases were observed where denser, surface snow was sliding on slightly older less dense snow.  As this snow settles out today, I’d expect slabs to become more cohesive at lower and mid elevations where they may be reactive to a skier or snowmachine. 

We continue to monitor a couple of known bed surface/ weak layers within our snowpack.  The first is a series of crusts/ facet combinations formed in late January.  Crusts are inherently slow to “heal” once buried and can act as a slick bed surface, promoting weak layers (facets) to form and persist for several weeks or more.  The good news is that this crust is only present in a rather concentrated elevation band between 1900-3000 feet.  The bad news is that crusts are persistent by nature and prove difficult to forecast for.

Then we have the deep slab issue that reared its head south of the Summit Lake region near Carter Lake on Monday.  Though we have not seen recent signs of deep slab instabilities in the Girdwood or Turnagain region recently, this incident is a good reminder that weak, basal snow does exist region-wide and is more easily triggered in shallow areas where a skier or snowmachiner can influence the bottom of the snowpack.