Scientists map step-by-step scenario of a Yellowstone supervolcano eruption

Ilan Kelman and Matthew Blackett explain that a sudden increase in deep earthquakes would be the first clue of magma movement beneath Yellowstone, leading scientists to upgrade the volcano alert within weeks. As unrest intensifies, erratic geysers and gas emissions would signal an imminent eruption, prompting authorities to designate a 100-kilometre evacuation zone affecting roughly 200,000 residents and many tourists.

The eruption would launch a 31-mile-high plume, dispersing ash in all directions before high-altitude winds carry fine particles across the United States, Canada and Mexico within a day. Within hours, superheated ash and gas would devastate nearby communities, causing up to 1,000 immediate deaths, while ashfall would shut down power, water, transport and communications for weeks. Agricultural loss, respiratory illness and strained health systems would follow, driving a global economic downturn and modest cooling of the planet’s surface. A decade later, survivors would face altered lifestyles and elevated mortality, illustrating the far-reaching consequences of such a super-eruption.