Turnagain Pass

Wind Slabs

Light density snow that fell early yesterday morning is now being transported to form new wind slabs.  Ridgetop winds picked up overnight and are now creating slabs up to a foot in depth.  The underlying bed surfaces supporting these wind slabs vary depending on elevation.  Between 1,000 and ~2,500′ these wind slabs are resting on a slick bed surface, formed by the warm temps of last week and the frigid temps of last weekend/early part of this week.  Expect to encounter the most sensitive slabs at the upper end of this elevation band, especially in open areas where the wind is blowing.  In the upper elevations wind slabs will also form and become sensitive today.  In addition, older pockets of wind slab that can cause problems are still out there as reported by a party on Magnum yesterday.

Loose snow avalanches

In wind sheltered areas above treeline expect to encounter loose snow avalanches running in steep terrain today.  While these avalanches are low in volume, the consequences increase if you’re swept off your feet or machine and into terrain traps such as cliffs, trees, and gullies.

Deep slabs continue to be a concern.  Weak snow that formed early in the season persists beneath dense snow that fell over the holidays.  We have seen evidence of this problem diminishing greatly below 2,000′.  Above ~2,000′ the weak base to the snowpack is still showing the ability to propagate across slopes and create large avalanches.  The reality is that it is very hard to initiate one of these avalanches.  The overlying slab is relatively strong and those weak layers have had time to adjust to the weight of the slabs sitting on them.  While it may seem that there are no problems on the surface, it is important to know the weather history of this season and realize that the weak snow is still there and capable of creating unsurvivable avalanches.