However, high level volcanic explosions do happen, as was the case with Mount Saint Helens in Washington ... On top of that, pyroclastic flows — an extremely hot and deadly current of volcanic ...

The most recent, 640,000 years ago, was a thousand times the size of the Mount St. Helens eruption in ... all the way to the Gulf of Mexico. Pyroclastic flows—dense, lethal fogs of ash, rocks ...