Yellowstone volcano: How summer tourists could face ‘unavoidable CATASTROPHIC effects’ 

The last eruption of Yellowstone produced around 2,500 times more volcanic material than the 1980 eruption of Mount St Helens.

This created an eruptive column so colossal that it covered around 60 per cent of the US in a thick layer of ash.

Should the same happen again, a mixture of ash, lava blebs, and superheated gas exceeding temperatures of 1,000C could move at speeds of up to 300mph. 

If the pyroclastic flow hits anyone, they would possibly die within seconds as the air could heat up to around 300C.