About 74,000 years ago, Toba erupted and ejected almost three times as much volcanic ash as the most recent major Yellowstone eruption (Lava Creek, 630,000 years ago) and about 12 percent more than Yellowstone's largest eruption (Huckleberry Ridge, 1.8 million years ago). That comes to several thousand times more material than erupted from Mount St. Helens in 1980.

Some researchers suspect that Toba's super eruption and the global cold spell it triggered might explain a mystery in the human genome. Our genes suggest we all come from a few thousand people just tens of thousands of years ago, instead of from a much older, bigger lineage — as the fossil evidence testifies. Both could be true if only a few small groups of humans survived the cold years following the Toba eruption.