[T]he Huckleberry Ridge eruption of present-day Yellowstone Park about two million years ago. . . was more than 2,000 times larger than the 1980 eruption of Mount St. Helens in Washington. . . . The Yellowstone eruption is one of the largest super-volcano events in history and it has happened several times. Other super-volcano sites include Lake Toba in Sumatra, the central Andes Mountains, New Zealand and Japan.
[D]espite its explosive history, it doesn't appear that Yellowstone is primed for another super-eruption anytime soon, though the slow process of volcanic uplift is taking place every day.
"The uplift of the surface at Yellowstone right now is on the order of millimeters. . . When the Huckleberry Ridge eruption took place, the uplift of the whole Yellowstone region would have been hundreds of meters high, and perhaps as much as a kilometer."
Indeed, the timing is right for climate impacts of the Huckleberry Ridge eruption to have triggered the first Out of Africa migration by hominins, specifically, Homo Erectus.