Super Mega Volcano!
The cataclysmic scenarios of the Yellowstone Super Volcano erupting have reached mythic proportions. It will consume the whole world! Humans will go extinct! It will burn up the western hemisphere! Lava will cover San Fransisco AND New York!
In reality, the likelihood of an eruption in our lifetime is low, and although the destruction would be devastating for much of the United States, overall, humanity will survive.
Check out this LiveScience article for an in-depth look at the consequences of a Yellowstone Eruption!