If yellowstone did go off how many people would be affected and where?

Question: If yellowstone did go off how many people would be affected and where?
- Keywords:
  yellowstone
Asked by thecatcannon to David on 24 Mar 2011 in Categories: Your Research.
- David Pyle answered on 24 Mar 2011:
  
  If there was a repeat of the last large explosive eruption of Yellowstone, then most of the mainland USA would be covered to 1 cm with volcanic ash. So, the eruption would affect a few hundred million people directly. Depending on the quantity of gas released in the eruption, there could be a significant global cooling for a few years.

Question: If yellowstone did go off how many people would be affected and where?