White Pass Backcountry

What a difference a few hours (or sometimes minutes) make! To start the day, cold, dry snow lingered on N-E aspects, providing smooth travel over settled powder. That changed quickly as the sun started to poke through the clouds and temperatures rose. Parades of rollerballs released mainly on shaded aspects, with a few pinwheels reaching 2-3 feet in diameter. Not surprisingly, natural wet loose avalanches soon followed. By noon, even shaded northerly aspects were becoming wet and sticky. The dry snow was no more. Ah spring time in the Cascades!

No cracking or collapsing.

On one hand, the upper snowpack is quite simple; recent snow is well bonded to strong underlying crusts. 

Through most of the terrain, last week's 16-18 inches of snow has settled to around a foot. Even though this wasn't the first warm or sunny day, the new snow has not fully transitioned to spring conditions (melt forms). A crust capped the recent snow on all but NW-N-ENE aspects. While the thickness of the crust changed from E to S to W, underneath the snow was still relatively dry. We could find a few subtle interstorm layers, but they weren't very concerning. The new snow was well bonded to the stout 4/14 crust. Both the 4/14 and 3/25 crusts were very evident in the upper snowpack. They are very strong and thick, easing concerns about anything deeper in the snowpack. At least for the moment. 

As temperatures warmed, the surface became wet and sticky on all aspects, even high northerlies. Rollerballs poured down the slopes. The greatest instability seemed to be on the same slopes where just moments earlier the snow was dry and soft. Even still, below the wet surface, much of last week's snow appeared to stay dry. 

We also found plenty of evidence of wind transported snow. Generally, NW winds created some odd loading patterns. While we could find wind slabs in the terrain, none failed. Only one uptrack test produced a short crack in a firm wind drifted pocket.