I don't think you have a clear idea of what happens when a supervolcano pops.

The Siberian Traps covered a million square miles with lava.

If Yellowstone goes off, N. America will be a graveyard from coast to coast. S. America will escape much of the devastation because the atmosphere doesn't mix well at the equator. Europe and Asia will be buried in ash, and billions of people will starve in the ice age that follows.

Not good.