The current coronavirus crisis has slowed down all tourism activities including sites and monuments in memory of the explosion of Mount St Helens. However, forty years later, nobody forgets.
On May 18, 1980, an earthquake of magnitude 5. 1 on the Richter scale triggered the eruption of Mount St. Helens. The colossal power generated wiped out 240 square miles of Washington State. It is one of the most devastating volcanic explosions in modern history. Still, forty years later, Mount St. Helens remains a threat.
That day, at 8:30 a.m., the earthquake shook the north face of Mount Saint Helens.
Scientists estimate that when the volcano erupted, its explosion was 500 times more powerful than the Hiroshima atomic bomb. It was the most destructive volcanic eruption in American history and one of the worst in modern human history.
15 minutes of absolute terror; the blast was felt as far as California, about 186 miles away. The blast is devastating. The floor is literally ripped off. Millions of trees and thousands of animals would not stand a chance against the fury of the volcano.
Within these 15 minutes, ashes and gases rise to 12 miles up and more. A huge dark cloud moves at more than 310 miles per hour. The extreme heat melts the snow turning it into a destructive mud river flooding the surrounding valleys: 250 houses, 47 bridges and nearly 186 miles of highways were destroyed. The intensity of the wave was equivalent to a tsunami. 240 square miles were literally wiped off the map of Washington State. For the next few hours, the region is plunged into darkness.
This cataclysmic chain of events killed 57 people and thousands of animals. Given the violence of the eruption, it is almost astonishing the human casualties were not worse. It is still to be noted that the first alerts had begun in March.
Indeed, then, a first earthquake of magnitude 4. 2 had already shaken the mountain, followed by several shallow ones. The situation had already put on alert the geologists and volcanologists of the U. S. Geological Survey (USGS). Their analysis showed that the quakes were pushing the magma up the chimney making its way to the surface. At that time, a state of emergency was declared.
It was not until several weeks later that Mount St. Helens started to deform. A bump on the north flank appeared. A dome that was rising two meters a day with continuous earthquakes. The sound advice of scientists that pushed the authorities to evacuate the area on the 14th of May 1980, saved many lives. It was only four days later that the explosion blasted.
From this blast some species survived. It provided nitrogen and carbon that allowed the vegetation and wildlife to recover. Insects now exist in these places that do not exist anywhere else.
But we know that the threat persists. Experts continue to monitor the Mount St. Helens, which lost 400 meters in height.
Hiking up the mount is possible today, but a permit is mandatory and is only available from March to November.
Translated by Laurene