Super Volcano Eruption?
The Yellowstone "super volcano" hasn't erupted in over 640,000 years, but when will it? Nobody knows. If this volcano were to erupt it would cause a world crisis disaster. If Yellowstone did erupt, it would erupt violently and produce about 10,000 times the amount of debris that the 1980 Mt. St. Helens eruption produced. More than half of the United States would likely be covered with ash. This would cut off the United States from the rest of the world and it would cause the entire world's economy to fall. There would also be thousands of deaths from the eruption. A Yellowstone eruption would a complete world devastation.
As you have seen in these videos a Yellowstone eruption would be awful for the entire world. Trade and all communication would be lost with the United States. Hopefully this will never happen; if it does hopefully we will have the science to know when it will erupt and we will be able to evacuate.