Want to know what it would be like? Really?
Go and study the years 536 to 538AD.
Only one thing. Time it times at least ten.
536 was the years the earth went dark for quite a while. There was one massive eruption...most likely Tambora and then a couple years later another BIGGER eruption most likely in Central America..Ilopango.
When the Yellowstone Caldera goes it’’s good night Irene for pretty much the whole USA.