Why is Yellowstone called a super volcano?

Unlike a regular volcano, a supervolcano can create an eruption which has the potential to “produce major effects on the global climate and ecosystem” (Google Dictionary). This means that the ecosystem and climate around the globe could be affected, instead of just the immediate area. The reason Yellowstone is considered a supervolcano is because, as numerous online sources and the previous answer all point out, there is a ton of hot water under the Yellowstone park.

That kind of climate could create a disastrous event if it were to explode. However, as many online sources say, this volcano is probably not going to unload its contents on us any time soon. While there are indications it’s getting ready to blow, many experts say that while it is overdue, it’s not close enough to cause mass panic yet.

Yellowstone national park contains a very large hydrothermal system - a lot of hot water underneath the earth crust. The volcano there, should it erupt, could obliterate all Life on Earth. This is why is is called a supervolcano.

Supervolcanos are those which have had an eruption of magnitude 8, which is the largest value on the Volcanic Explosivity Index (VEI). Recent measurements in Yellowstone do raise concerns that heat levels, onl 5- 10 miles under the earth, are higher than had previously been predicted.