Mount St. Helens Pictures: Before and After the Blast

Fuming Mount St. Helens

Photograph courtesy Lyn Topinka, USGS

A steam plume rises from the gaping maw of Mount St. Helens two years after its May 1980 eruption.

The blast was so powerful that it destroyed the top 1,300 feet (400 meters) of the volcano, leaving a crater 2 miles (3.2 kilometers) wide.

Some of the first colonizers of the bleak, post-blast mountain were insects blown in from afar—although some died instantly in the baked landscape, said University of Washington professor emeritus John S. Edwards.

(Explore a time line of life returning to the blast zone.)

Published May 18, 2010

Mount St. Helens Aerial, 1973

Image courtesy NASA/USGS

The white, snow-capped dome of Mount St. Helens stands out against green forests in a 1973 aerial view from a NASA Landsat satellite.

Before the blast, the volcano's icy peak rose more than 5,000 feet (1,500 meters) above its base, which was surrounded by forests dominated by tall fir trees.

When the volcano erupted in May 1980, much of the surrounding forest was engulfed by pyroclastic flows—superhot clouds of ash, rocks, lava, and gases that hurtled down the volcano's flanks at speeds of up to 500 miles (800 kilometers) an hour, Washington State's Swanson said.

The heat and speed of the pyroclastic flows killed a lot of trees, he added.

Published May 18, 2010

Mount St. Helens Aerial, 1983

Image courtesy NASA/USGS

Forests on the north face of Mount St. Helens still appear as gray ash fields a few years after the eruption, as seen in a 1983 Landsat picture.

The barren landscape provided new opportunities for some new tree species. Pre-eruption forests around Mount St. Helens were mostly made of Douglas firs. But the current forest cover is heavily populated by trees such as red alder and willow, which have light seeds that disperse easily in the wind.

Many of the first trees to recolonize the volcano after the blast were reliant on the corpses of dead insects for nutrients such as nitrogen and phosphorous, the University of Washington's Edwards said.

"The bug bits tended to get blown into microcrevices in the landscape, which is where seeds blow," he said. "So in a very rudimentary way, the seeds germinated in bug compost."

Published May 18, 2010

Mount St. Helens Aerial, 2000

Image courtesy NASA/USGS

By 2000 the charred landscape around Mount St. Helens was showing signs of healing, as seen from a Landsat satellite.

"When the blast first occurred, the region looked fairly lifeless, but it's become a very rich environment over the last 30 years," Washington State's Swanson said. (See pictures of life returning to Mount St. Helens.)

Regions that were wetter and not constantly exposed to harsh winds have recovered faster, he said, while dry ridge tops that had shallow soil before the eruption have taken longer to bounce back.

"You're going to have a very slow recolonization processes there, and the trees will only gradually encroach back in."

Published May 18, 2010

Spirit Lake Basin

Pictures courtesy U.S. Forest Service

Douglas firs, Pacific silver firs, and mountain hemlock seemed to block the sky over old-growth forests around Spirit Lake, as seen in a picture taken in 1979 (left) by the U.S. Forest Service.

A year after the 1980 Mount St. Helens eruption, the same plot of land lies buried beneath large blocks of volcanic rock, or pumice, sent hurtling down the volcano by pyroclastic flows (right).

This rock-strewn region is among the parts of the volcano's ecosystem that will likely take the longest to bounce back, Swanson said.

"Different regions have different trajectories of recovery," he said. "There are some areas that aren't going to recover for decades or maybe centuries."

Published May 18, 2010

Lying in Wait

Photograph courtesy R.M. Krimmel, USGS

An aerial photograph of Mount St. Helens taken on May 4, 1980, shows the volcano days before its infamous eruption. Mount Hood in Oregon is just visible on the horizon (top right).

In the months leading up to the blast, the volcano showed signs of unrest, including earthquakes, smoking steam vents, and small eruptions of lava.

On May 18 a magnitude 5.1 earthquake triggered the powerful detonation that blasted away the top of the volcano. (See a picture of Mount St. Helens erupting on the morning of May 18, 1980.)

Published May 18, 2010

Smoking Summit

Photograph courtesy Robert Krimmel, USGS

The view from roughly the same angle in 1982 shows the obliterated north face of Mount St. Helens sitting in contrast to Mount Hood's snowy peak.

Magma rising into the volcano from Earth's interior triggered the earthquakes, which ultimately caused Mount St. Helens to erupt, said University of Washington professor emeritus Steve Malone.

The May 18 eruption was more powerful on the north side, because earthquake-triggered avalanches in the weeks leading up to the blast had weakened that part of the volcano's structural integrity.

"Earthquakes were banging away at it at a fairly regular rate," Malone said. "One more was just enough, until finally [the volcano's surface was] weak enough that it just let loose."

Published May 18, 2010

The Day Before

Photograph courtesy Harry Glicken, USGS

Mount St. Helens rises above the surrounding old-growth forests in a photograph taken from Johnston's Ridge, six miles (ten kilometers) northwest of the volcano, a day before the 1980 eruption.

Snowbanks that had accumulated along the volcano's slopes before the eruption offered an unexpected refuge for some of the shorter trees and plants that normally form the understory of forests, Washington State's Swanson said.

"So you had herbs and shrubs and shade-tolerant trees that were protected from the force and the heat of the blast," Swanson said. "In some areas, you had a ready-made forest community that could spring right up" after the blast.

Published May 18, 2010

Smoldering Peak

Photograph courtesy Harry Glicken, USGS

Another photograph taken from Johnston's Ridge in September 1980 shows the largely barren landscape surrounding Mount St. Helens's crater.

Malone, the retired director of the University of Washington's Pacific Northwest Seismic Network, called the 1980 Mount St. Helens blast a "baptism by fire" for him and his colleagues.

"Here in the Pacific Northwest we had little experience with volcanoes in our backyard," he said.

"We had to transition very quickly from being a pure research institute to one whose work had real value to public safety." (Read a first-hand account of the eruption published in the January 1981 issue of National Geographic magazine.)

Published May 18, 2010