It is hard to imagine when viewing the pristine beauty of Yellowstone, its caldera and many geysers, that this picturesque environment is a powder cake waiting to explode. Yellowstone is a huge volcano that sits right on the continental divide, right smack on the edge of two continental plates where the Rocky Mountains rise up in jagged succession across the landscape and evidence of the activity of the earth is not far away.
Yellowstone has four main thermal and volcanic features, including geysers, hot springs, fumaroles and mud pots. The most famous geyser is Old Faithful, which has been increasingly active, all resulting from the movement of molten metal and rock far beneath the earth's surface superheating the underground water supplies and causing them to boil over. In fact, the geysers are the planet's plumbing, small tears in the crust that allow the escape of steam very similar in nature the release valve on a pressure cooker. However, the geyser is the preventative measure that does not allow the water to boil over, merely to release the expanding steam and excessive pressure when needed. So as the pressure reaches beyond the capacity of the water to stay within its boundaries, a flash explosion of super hot steam is forced through the tiny crack, sending water high into the air. The hot springs are spread across the landscape, even as far away as Mammoth Hot Springs, were water is warmed by molten fluids beneath the surface, filling the water with different levels of carbon dioxide and an acid that can dissolve even rock. Sometimes that carbon dioxide escapes, superheating the water, but in some cases, the acid comes with it making some hot springs too dangerous to use. Fumaroles in Yellowstone are probably the most fascinating of all the features as they are simply steam vents where little water is present. Simply groundwater is instantly evaporated by the high temperatures of ground rocks and this steam is forced out through the cracks in the surface, making a roar or even a mild hiss. The many mud pots are merely clay that has been dissolved by carbonic acid and the water has mixed with this into a brown mud when combined with different surrounding minerals. As a result the mud is extremely acidic and very dangerous.
Evidence of previous eruptions and potential eruptions are everywhere in Yellowstone. Whole acres of land have been blocked to visitors after many years of dying trees and animals within those areas. Old lava flows still sit silent for all to see and evidence of volcanic ash has been discovered even in California. Put bluntly, Yellowstone is many times worse than Krakatau in Asia could ever be. In fact, evidence of its violent past has even been found in Saskatchewan in Canada. Such an eruption of that magnitude is expected again, and scientists shed no doubts on the fact that the devastating effects of a Yellowstone super volcano eruption could cause serious destruction and death along the whole of the eastern seaboard of the United States, affecting global weather patterns for possibly even centuries.