Remember all that choking gorp that filled the streets of New York after the towers collapsed? St. Helens' expulsions were much worse. I lived far enough north of St. Helens, in south Seattle, when it blew in 1980 that I just got the fallout of the fallout, while the winds took the ash largerly east and south (although the ash rolled over Olympia in heavy quantities). It was absolutely appalling, no sunlight, cars couldn't be driven, etc. When the towers fell, it brought back some memories. The noise of the eruption was a shock coming out of "nowhere" -- never heard another sound to equal it.
I remember the ash from Helens chewing jet engines and windows apart.
I was just checking the USGS earthquake site
http://earthquake.usgs.gov/recenteqsUS/Maps/US2/45.47.-123.-121.html
there were 2 earthquakes under the lava dome in the last hour 2.4 and 2.5 on the richter scale.