On the 18th of May, 1980, a massive volcanic eruption took place at Mount Saint Helens
– an active volcano located in the state of Washington in the USA.
This massive explosion had been preceded by months of lesser volcanic and seismic activity…
but nonetheless nobody was prepared for the scale of the disaster which ensued.
The eruption of Mount Saint Helens would claim more than 50 lives, cause billions of dollars
of damage, and have a lasting impact on a massive swathe of the country.
Mount Saint Helens is a relatively young volcano, having only formed within the last 40,000
years.
Prior to the 1980 eruption it stood around 1,500 metres (or 5,000 feet) tall, making
it one of the tallest peaks in Washington state.
It is one of a number of volcanoes to be found in western North America in an area that is
known as the Cascade Volcanic Arch.
Like many volcanoes, Mount Saint Helens goes through periods of activity and periods of
dormancy.
For example, a 57-year period of activity began with a massive eruption in 1800.
Throughout this period of activity many small eruptions were recorded, some of which sent
clouds of ash drifting over Washington, Idaho and Montana.
These frequent eruptions stopped around 1857, and the volcano entered a period of dormancy
that would last for around 123 years.
During those 123 years, the area around the volcano was developed.
By 1980, logging was a significant industry in the region, many roads and bridges had
been built, and dozens of small settlements had taken root.
Early in 1980, Mount Saint Helens began to show signs of entering an active period again.
Dozens and then hundreds of minor earthquakes shook the ground, and the volcano was occasionally
seen to spew smoke, ash or steam.
A bulge began to develop on the northern side of the mountain, growing day by day.
Scientists were called in to monitor the volcano, and noted that the bulge was likely due to
magma rising up from a fault deep underground.
While these developments were concerning to scientists, they also drew hundreds of sightseers
to the area to watch the now-frequent eruptive activity from what they believed to be a safe
distance.
Local law enforcement attempted to turn people away, but given the size of Mount Saint Helens
and thus the size of the area from which it could be observed, policing every road and
byway was impossible.
Instead, on April 3rd, Governor Dixy Lee Ray declared a state of emergency, and requested
that people stay away.
Even with the support of the National Guard, it was only possible to dissuade some of those
who wanted to enter the area, and so on the 30th of April a “red zone” was established
around the mountain.
This zone was the area that might well be devastated should there be a vertical eruption
from the volcano – something that seemed increasingly likely day by day.
Within this zone only scientists, law enforcement personnel and journalists were allowed.
Also established was a slightly larger “blue zone”, which more people, including loggers,
were allowed to access.
There was considerable anger around these new danger zones.
Some loggers wanted stronger action, perhaps even to be forbidden from working in the area
at all.
If they were allowed to work there, they were under pressure to do so in order to keep their
jobs, even if they felt unsafe.
At the same time, people who owned houses and cabins within the danger zone keenly wished
to be allowed to return to retrieve their possessions.
Some residents even refused point-blank to leave.
In the week before the eruption, plans were underway to create an expanded no-entry zone
around the volcano.
However these plans were delayed several times, and only reached the desk of governor Dixy
Lee Ray the day before the eruption – a Saturday, when she was busy attending a local
parade.
The following day, the 18th of May, at 8:32am, another earthquake took place centred directly
below the northern slope of Mount Saint Helens.
This tremor caused a huge portion of the mountainside to move, creating the largest landslide in
recorded history which raced downhill at around 249 kilometres (or 155 miles) per hour.
As well as causing significant devastation in and of itself, the landslide weakened the
side of Mount Saint Helens, triggering a lateral eruption of hot volcanic gasses, ash and rock.
This explosion projected from the side of the mountain, and so covered a much larger
area than the vertical eruption that had been anticipated might have.
A pyroclastic flow (a dense, fast-moving cloud of hot gas, ash and rock) completely destroyed
everything inside a fan-shaped zone within a 13 kilometre (or eight mile) radius.
Beyond this zone of complete destruction, the effects of the blast were varied.
Some areas were flattened, while others survived, having been shielded by the shape of the landscape.
Trees were burned up to 30 kilometres (or 19 miles) away.
In addition to the damage caused by the explosive power of the eruption, a massive cloud of
ash was ejected from the volcano, rising high into the atmosphere.
The ash particles in the air caused lightning, which started numerous forest fires, while
at the same time ash clouds cast a pall over adjacent states.
This ash was problematic: it clogged machinery, short circuited electrical transformers, killed
livestock, polluted drinking water, disrupted air travel, and reduced visibility to such
a degree that it caused several traffic accidents.
In addition to this, the eruption also liquefied several mountain glaciers, causing fast-moving
mudflows that swept along river channels, destroying riverside properties and sweeping
away bridges and other infrastructure, burying the landscape in mud.
In total, at least 57 people died as a result of the eruption of Mount Saint Helens – though
the death toll might have been higher, as some bodies were never found.
These deaths included 30-year-old volcanologist David Johnston.
On behalf of the US Geological Survey he had been observing the volcano from a post situated
at what had been thought to be a safe distance.
His observations had helped to persuade authorities not to reopen the red zone around the volcano,
thus considerably reducing casualties from the disaster.
Also killed was 48-year-old photographer Robert Landsburg, who witnessed the eruption, and
in his final moments shot a series of photographs of the mountain.
He then rewound his film into its case, stowed it in his backpack, and shielded this pack
with his body as the pyroclastic flow swept over him.
He was killed, but geologists were able to save the film and develop his final pictures,
providing them with valuable information about the eruption.
83-year-old lodge owner Harry Truman (of no relation to the US president of the same name)
also perished in the eruption.
He had famously refused to leave his home in the weeks prior to the disaster, insisting
that – though he was afraid – he would not leave the home and life that he and his
late wife had built.
He and his 16 pet cats were killed by the pyroclastic flow.
While many people who had been in the area stood no chance of survival, there were a
number of remarkable rescues.
National Guard pilot Jess Hagerman spent days flying through dense clouds of ash with negligible
visibility, navigating as best he could given that most landmarks in the area had been destroyed
or buried.
He rescued two members of a logging crew, and later a family who had been hiking through
the blasted landscape for more than a day with their infant child in a backpack to protect
her lungs from the ash.
As time went on, rescue activities wound down and a lengthy and expensive cleanup process
began.
The combined effects of the blast, the ash clouds and the mudflows had destroyed 200
homes, 47 bridges, huge lengths of road, and a significant amount of logging infrastructure.
Forests close to the site of the eruption has also been devastated, with thousands of
trees flattened or swept into rivers.
It was both a human and an environmental catastrophe.
Roads and bridges were rebuilt or repaired.
Nine hundred million kilograms (or 900,000 tonnes) of ash were removed from roads, and
routes into affected areas were eventually re-established, with loggers beginning work
again towards the end of the year.
Over the course of years and decades, plants and animals slowly returned to the devastated
area around the volcano, providing scientists with a unique insight into how nature recovers
following this kind of massive disruption.
Even as the area slowly recovered, Mount Saint Helens continued to be active.
From 1980 to 1986 there were numerous smaller eruptions, none of which were on the scale
of the 1980 disaster.
More recently there was a significant amount of activity in the early 2000s, with small
eruptions of ash and steam, and new lava domes forming in the crater of the volcano.
Scientists continue to monitor the volcano closely.
While the size of eruptions cannot be predicted far in advance, it is likely that – just
as there was in 1980 – there will be some warning of an impending large eruption.
When this warning is observed, the actions taken in response will determine the severity
of the next eruption of Mount Saint Helens.