My question is, statistically how much of a variation from the norm over the past.. 20-30 years is this?
Since eruptions are tens to hundreds of thousands of years apart, depending on the size, I'm not sure such short time periods of 20-30 years are meaningful.
My other question is, other than don't breath the portland cement if you can avoid it, what do people expect to do during the ashfall?
Probably wonder how much uncontaminated drinking water will remain west of the Mississippi in 72 hours...