Turnagain Pass

The shocker over the past two days in the field was just how much snow there is available for transport above ~1,500’.  Moderate southeasterly winds have been able to move snow and build shallow wind slabs over the past two days.  Though winds began to subside yesterday afternoon, it will be possible to kick off a lingering wind slab today, particularly on north and west facing terrain above where the snow surface dries out.  Cross loaded gullies and mid-slope convexities that sport a smooth, rounded look or hollow feeling snow should be suspect.  Any shooting cracks as you step out of the skin track or off your sled should be a bull’s eye clue that you’re dealing with a wind slab issue.  Relatively benign weather today shouldn’t be adding much additional stress to the snowpack, but finding a lingering wind slab will still be possible in the upper elevation areas harboring dry snow.

Moderate southeasterly winds over the past two days have been enough to build wind slabs in leeward terrain.  Photo: Comet Peak in the Placer Valley, 4.6.22.

Wet loose: Expect mostly sunny skies to heat up southerly slopes this afternoon/ evening.  As we’ve seen the last couple of days, natural and human-triggered wet loose activity will be on the rise later in the day.  Though likely a manageable problem, there is potential a wet loose avalanche could step down to a known crust/ weak layer combo from the beginning of April.  More on that below.

Cornices:  They’re as big as they’ve been all season and today’s weather/ snowpack will allow folks to be travelling along ridges.  Give cornices an extra wide berth and don’t let your guard down as you move along a corniced ridge toward your objective.

The crust/ weak layer combo affectionally referred to as the ‘April Fool’s interface’ (given the date it was buried) is proving more stubborn in snow pit tests as the week goes on.  That said, this was the culprit in an active natural avalanche cycle last weekend and most recently, a skier triggered avalanche on Monday in the Seattle Creek area.  The interface is 1-2’ deep now and though unlikely to trigger, the structure (crust/ surface hoar/ facet combo) is concerning enough that we can’t forget about it.  A lingering wind slab, cornice fall or wet loose avalanche could provide enough of a punch to step down to this April Fool’s interface, particularly on steep, unsupported slopes.

Deep Persistent Slabs: 

If you’ve been following along over the past several weeks, you’ll know that buried 3-6’ down in our snowpack we have a couple other persistent weak layers we’re tracking.  This is a low probability, high consequence avalanche problem right now meaning it’s very unlikely to trigger an avalanche this deep but if you do, it’d be very large given the depth of the weak layer.  We’ll continue to track these layers with any new loads or rapid warming events as our snowpack continues its inevitable transition toward whitewater rapids and salmon habitat!