Experts warn of 90,000 immediate deaths and a 'nuclear winter' across the US if supervolcano erupts
A supervolcano in the heart of America's northwest has the potential to blanket the US in a 'nuclear winter'.
If it were to erupt, the Yellowstone supervolcano would be one thousand times as powerful as the 1980 Mount St Helens eruption, experts claim.
While it has lain dormant for more than 70,000 years, scientists say that we can't rule out the possibility eruption this may some day take place – although they say the chances are extremely slim.
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The volcano at Yellowstone National Park in Wyoming and Montana sits atop a huge reserve of molten rock and last erupted 640,000 years ago.
It is one of the largest active continental silicic volcanic fields in the world. Silicic is used to describe magma or igneous rock rich in silica.
Experts say there is a one in 700,000 annual chance of a volcanic eruption at the site.