On May 18, 1980, Mount St. Helens erupted, blowing 1,300 feet off the mountain and killing 57 people.
In a 2005 Willamette Week retrospective, Patty Wentz wrote about the significance of the event.
Mount St. Helens didn’t merely erupt on the morning of May 18—it exploded. This is it!’ exclaimed meteorologist David Johnston over the radio from nearby Coldwater Ridge, seconds before the mountain detonated. Those were his last words. He was one of 57 people who died that day, including mountain man Harry Truman, who refused to believe St. Helens would really blow.
St. Helens would clear her throat again 25 years later—a mere hiccup compared to the 1980 blast, which set off the biggest landslide in recorded history, spewed 3.5 billion cubic yards of molten rock, unleashed 24 megatons of thermal energy, and blew down enough trees to build 300,000 houses. So much debris fell that 31 ships stranded in the Columbia River, and Portland was blanketed in a apocalyptic layer of gritty ash that puffed up from the ground with every step.
The explosion, which shot ash 80,000 feet in the air, was so major, it could be seen in space.
Today, one of the least-appreciated government agencies, the National Environmental Satellite Data and Information Service (NESIDS), released video showing what the eruption looked like from space.
Seattle's National Weather Service also posted this video of the explosion, showing a bright burst of infrared.
Here's the original KGW broadcast of the event.