When will Yellowstone blow?

The Grand Prismatic Spring, the largest in the United States and third largest in the world, is...

The Grand Prismatic Spring, the largest in the United States and third largest in the world, is seen in Yellowstone National Park, Wyoming, June 22, 2011. Picture taken June 22, 2011. (REUTERS/Jim Urquhart)

Kevin Maimann, QMI Agency

, Last Updated: 3:08 AM ET

EDMONTON — Imagine a thick fog closing in on much of Western Canada.

As you step outside under the blotted sun, you’re covered in sharp, grey particles that blanket the streets.

Scientists have discovered Yellowstone National Park supervolcano is two-and-a-half times larger than previously thought, and it could erupt with 2,000 times the force of Mount St. Helens — a blast that would devastate North America and dump more than 10 cm of ash on Western Canada alone.

The national park and surrounding communities would be annihilated, while plants and entire farms hundreds of kilometres away would be wiped out. Escape would be futile — ash damages commercial aircraft engines, making flight hazardous.

Sulfur entering the upper atmosphere would turn to sulfur dioxide, circle the globe and drop temperatures. Worldwide famine would likely ensue.

“There’s not a whole lot you could do,” said Jamie Farrell with the department of geology and geophysics at the University of Utah.

“Once this thing revs up, there’s nothing you can do to stop it.”

Farrell is the lead author of a study presented at the American Geophysical Union Fall Meeting in San Francisco in December that determined the magma chamber beneath the Yellowstone caldera is 88 km long and 29 km wide, reaching depths up to 15 km. That makes it the largest imaged magma reservoir in the world.

But is an eruption in the cards? No one really knows.

“There may not be, but there probably will be. Of course, we don’t know when,” Farrell said.

The popular Wyoming tourist destination lies on a depression in the ground created by a major eruption 640,000 years ago. The hot springs, boiling mud and geysers that dazzle visitors are merely a glimpse into the molten rock that stirs below.


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