Because humans have almost never gone there for 60 years, th 2 6, 2:02am

@Klaus It's going to be worse than that: the volcanic ash in the air will cause massive weather instabilities across the globe. When Tambura erupted in 1815, the ash it put out caused such low temperatures across North America and Europe that 1816 was known as the year without a summer. And Yellowstone is a *much* bigger volcano.