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.)
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).