The 1936 Yellowstone Eruption, also known as the Yellowstone Event or Eruption Day, was a supervolcanic eruption that occurred on the morning of July 18, 1936 at the site of the Yellowstone National Park. It has been considered the largest eruption in recorded history, and perhaps the largest volanic eruption in history. Tens of thousands died over the first number of days following the eruption, and the ash deposited in the atmosphere led to a worldwide volcanic winter lasting for twelve years (with cooling effects lasting well beyond then), as well as mass crop failure and famine, which furthered the death toll into the hundreds of millions; the most deadly natural disaster in human history.