41 Years Ago, Mount St. Helens' Eruption Shook The Pacific Northwest
By Zuri Anderson
May 18, 2021
Mount St. Helens stood silent for over a century until May 18, 1980.
A 5.1 earthquake shook the mountain, leading to the historic eruption that people and scientists look back on 41 years later.
"May 18, 1980, changed how we look at geological hazards," Dr. Vicki McConnell, then Oregon's state geologist, said in 2008.
Weeks before the mountain roared back to life, geologists noticed ash spewing from the top of the volcano in March 1980. Over 2,800 earthquakes were recorded between then and the fateful day, according to the U.S. Geological Survey (USGS). A bulge also started developing on the volcano's left side.
That bulge bursted thanks to the 5.1 earthquake that rattled the mountain. An explosion blew out the side of the mountain, causing a landslide and depressurizing the St. Helens' magma system, the USGS said. That's when the top of the mountain blew off.
When the eruption did happen just after 8:30 a.m., KING 5 said the blast reduced Mount St. Helens was reduced by 1,314 feet. Smoke from the volcano could be seen from satellites orbiting space. Ash blankteted the Pacific Northwest and was found in 11 other states and Canada.
Fifty-seven people died from the eruption, making this the deadliest eruption in U.S. history. Birds, mammals and big game animals also died in the event. The blast destroyed over 150 miles of highway, 200 homes and 15 miles of roadways, the USGS found.
Forty one years ago on the morning of May 18, 1980, a magnitude 5.1 earthquake triggered the collapse of the summit and north flank of Mount St. Helens and formed the largest landslide in recorded history. https://t.co/15YOgu42RT pic.twitter.com/ye2B7lnfk6
— Gifford Pinchot National Forest (@GPNF) May 18, 2021
"The International Trade Commission determined the total cost of damage and rebuilding efforts from the eruption came to an estimated $1.1 billion," KING 5 wrote.
Seismic activity calmed down following Mount St. Helens' eruption, with some significant explosions happening in the early to mid-2000s. It remains the most active volcano in the Cascade Range, and it may erupt again in our lifetimes, according to the USGS. Reporters noted that a blast like the 1980 eruption is unlikely due to a deep crater.
"A volcano may go into an eruptive state tomorrow," McConnell said in that 2008 interview. "The question is are we ready?"
Photo: Getty Images