By Michael Lanza
The snowcoach rumbles away, leaving us in a wintry silence disturbed only by a slight breeze and the gastrointestinal emissions of a supervolcano that last let out a really big one 640,000 years ago. Back then, it ejected about 240 cubic miles of rock and dust into the sky. Today, as seems always the case with these things, it just sounds a little rude and smells badly.