Monday, May 23, 2016

ANNIVERSARY - Mtount St. Helens

"From Mt. St. Helens' volcanic ashes, Mother Nature rebuilds" PBS NewsHour 5/18/2016


SUMMARY:  Wednesday marks the 36th anniversary of the deadliest volcanic event in U.S. history: the eruption of Mount St. Helens, which killed every living thing in a 230 mile radius.  But the slopes around the volcano are now beginning to repopulate with plant and animal life, giving biologists a unique opportunity to watch an ecosystem develop in real time.  Science correspondent Miles O'Brien reports.

MILES O'BRIEN (NewsHour):  Thirty-six years after its spectacular, deadly eruption, Mount St. Helens still rumbles and bears scars from that earth-shattering day.

But hike down the slopes, away from that jagged crater just a little, and you will see Mother Nature hard at work.  And there's a good chance you will bump into a team of scientists led by John Bishop.  He is an evolutionary biologist at Washington State University-Vancouver.

JOHN BISHOP, Washington State University-Vancouver:  The goal of our research is to understand how plant and animal communities reform after a catastrophic disturbance.

MILES O'BRIEN:  Bishop is one of a select group of researchers studying this rebound from a volcanic eruption.  Back in 1980, Mount St. Helens had given scientists all kinds of clues that a big disturbance was brewing.

Two months before it blew, the volcano was venting huge amounts of steam and there was a series of earthquakes.  Even with all those ominous signs, the eruption was larger than anyone predicted.  It happened at 8:32 on the morning of May 18, 1980.  An earthquake caused the north face of the mountain to collapse.

JOHN BISHOP:  After that, it uncorked an explosion that was directed horizontally, and leveled the forest to 13 miles out from the volcano.

MILES O'BRIEN:  The eruption column of volcanic ash and gas rose 80,000 feet, while a tsunami of 1,800-degree gas and rock raced down the valley at 450 miles an hour, a so-called pyroclastic flow.

JOHN BISHOP:  Anything biological that was remaining after the landslide would've been completely vaporized.  It was just a barren landscape, gray and pumice-colored.

MILES O'BRIEN:  It killed every living thing in a 230-square-mile area.  What was left was akin to a moonscape; 57 people died.  Some remains were never recovered.

Bishop and his team have had a front-row seat as nature got busy bringing this place back to life.  They wanted to know where it begins and how it takes root.  Here, it started with these purple flowers.  Alpine lupine were the first plants to return.  For many years, they were pretty much the only game in town.  But as they went through their life cycles over several seasons, they created soil from the volcanic ash.

And that made it possible for woody plants, like the Sitka willow, to find a home.  They are how a forest gets started, but it hasn't been easy for them.

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