Yesterday was the 35th anniversary of the 1980 eruption of Mount St. Helens. I've commemorated the anniversary once before when I posted an Accuweather video as the second of Two environmental videos from Accuweather. This time, I'm sharing the full video of the NOVA episode 'Mount St. Helens Back from the Dead' from 2010, a clip of which I show my students to begin my lecture on volcanoes and vulcanism. It definitely gets their attention.
An eruption like this won't cause the collapse of civilization, but it can certainly ruin a city. Just ask the Romans.* On the other hand, a supervolcano eruption could contribute to the downfall of a civilization. I might blog about that one of these days.
*I might deliver an answer the next Ides of March.