Our newsroom has been consumed just keeping up with fresh information about the flooding and storm impacts.  No time this week for a deeper look at anything.  But, this would have been a good topic:  Mark Moore of the Northwest Avalanche Center grabbed my attention during a news conference about the weather on New Year’s Eve.

He declared that the avalanche danger had become  “extreme.”  He explained, with a series of slides, how it’s not just having a large snowfall that makes for an avalanche.  It’s the type of snow and the temperatures during each successive snow-storm that make for a big hazard.  We saw this come true on the mountain passes last week, and especially this week.

This landslide/avalanche near Snoqualmie Pass took out not only all the layers of snow, but several  inches deep of soil as well — and a ski lift.  (I haven’t done any deeper research on this, but I’m pretty sure it has the same fundamental cause as the all-snow avalanches.)

Avalanche and landslide at Hyak (Snoqualmie Summit East) (WSDOT)

Check out the full gallery of photos posted by WSDOT.

And for a nice info-graphic explaining the underlying science, plus a profile of the scientists, see Tom Paulson’s story in the P-I (published just before the Hyak slide came rumbling down).