Yellowstone supervolcano: What happened 631,000 years ago and what if it erupts again?

The last significant eruption of Yellowstone happened around 631,000 years ago, resulting in the formation of the caldera. Experts argue that while smaller volcanic events are more probable, a monumental eruption remains unlikely. If it were to occur, ash fallout could paralyze transport and farming across the nation, and volcanic gases might temporarily bring down global temperatures, shifting weather patterns.