This week marked the forty-first anniversary of the eruption of Mount St. Helens, which took place on May 18, 1980.

For the occasion, the NOAA Satellites Twitter account sent a tweet showing footage of the eruption from space. Those images were taken by NOAA's third Geostationary Operational Environmental Satellite (GOES-3).

Famous photographs from the ground were also taken that day.

“It was the deadliest and most economically destructive volcanic event in U.S. history,” the tweet said, while also linking to a commemoration from 2020, which was the fortieth anniversary of the eruption.

“Shortly after 8:30 a.m. PDT on May 18, a huge earthquake caused a mile-wide portion of the mountain’s north face to collapse,” the site’s description said.

“The eruption produced a force equal to 10–50 megatons of TNT, the equivalent of 25,000 atomic bombs released over the city of Hiroshima during World War II, and superheated gas and rock exploded out of the volcano sideways at speeds of up to 400 mph. It was followed by a dense plume of thousands of tons of scorching ash that spewed 12 to 16 miles up into the atmosphere, turning the sky dark and the air suffocatingly thick. As 46 billion gallons of slush and water began to race down from the snow-capped mountain, it collected tons of mud, rocks, and trees. This lethal debris slurry, called a lahar, destroyed everything in its path.”

“It wasn’t the first eruption to be caught on satellite,” Tim Schmit, a satellite research meteorologist at NOAA’s Center for Satellite Applications and Research in Wisconsin, told the website for the 2020 commemoration. “Since polar-orbiters had detected many over the years, and nor was it the first seen from a geostationary satellite.”

NOAA also said that its satellite photography equipment has improved considerably in the more than forty years since the Mount St. Helens eruption. The GOES-3 satellite, for example, could only see through two spectral bands. The current satellite, the GOES-R, carries the Advanced Baseline Imager (ABI), which include sixteen bands. They were able to provide much clearer photographs when the Ubinas volcano in Peru erupted in July of 2019.

KING 5, also in Washington state, also remembered the eruption this week, on its anniversary. It noted that the explosion killed fifty-seven people—making it the deadliest volcanic eruption in U.S. history—and caused more than $1 billion in damage.

“A 5.1 earthquake on May 18 rattled the mountain, causing the bulge to burst and landslide down the mountain. Once the bulge was gone, the volcano's magma system was depressurized and blew off the top of the mountain,” the TV station said.

Stephen Silver, a technology writer for The National Interest, is a journalist, essayist and film critic, who is also a contributor to The Philadelphia Inquirer, Philly Voice, Philadelphia Weekly, the Jewish Telegraphic Agency, Living Life Fearless, Backstage magazine, Broad Street Review and Splice Today. The co-founder of the Philadelphia Film Critics Circle, Stephen lives in suburban Philadelphia with his wife and two sons. Follow him on Twitter at @StephenSilver

Image: Reuters.