The Risk Of Yellowstone's Mighty Volcano

The tourists are showing up as the season gets going at Yellowstone National Park, some of them oblivious to what lies beneath.

"The volcano?" asked a young woman who had just started her summer job in West Yellowstone.

"I've heard about the one in Iceland, not the one in Yellowstone."

The volcano in Iceland has CBS station KCNC-TV thinking about the power that's roiling under the earth's surface. The Iceland volcano forced airlines all over Europe to cancel flights because the ash -- tiny particles of glass can clog and damage engines as it hits at hundreds of miles per hour.

If the Yellowstone volcano has a major eruption, you won't be thinking much about flying.

"Almost everybody knows something about Mt. St. Helens," said the US Geological Survey's Dr. Harley Benz.

Benz is scientist in charge at the USGS office in Golden. He's busy tracking earthquakes these days, but spent five summers in Yellowstone writing his master's thesis on the volcano. Benz explained there are three known major eruptions, 2.1 million years ago, 1.3 million years ago and 640 thousand years ago.

In the eruption 640 thousand years ago, the ash was 1000 times greater than Mt. St. Helen's. And that wasn't the biggest. When the Yellowstone volcano went off 2.1 million years ago scientists figure is pushed out 585 cubic miles of material. When Mt. St. Helens erupted 30 years ago this week, it ejected one-10th of a cubic mile of material. Do the math -- that's about 6,000 times the size of Mt. St. Helens.

"We're talking about a huge area that was covered in tens of feet of ash," said Benz. "In a very large area out to 100 miles from the center."

Ash would cover a large portion of the western United States.

In Denver, 500 miles away from Yellowstone, we've seen 2 to 3 feet of ash in past super eruptions.

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