SKAMANIA COUNTY, Wash. -- It's known as the explosion heard around the world: 40 years ago today, Mount St. Helens erupted, leaving a path of destruction throughout the Pacific Northwest.
Many people saw it coming. They watched for two months, waiting for it to blow.
James Erickson, author of the book "Memories of Mount St. Helens," was a journalist at the Tacoma News-Tribune in 1980. He had been covering the activity at Mount St. Helens since late March, when minor eruptions and earthquakes started happening.
"I was waiting because I knew the mountain was going to do something. That bulge was getting huge on the north flank," Erickson recalled.
For two months, it was a waiting game - until May 18, 1980.
It was a warm, sunny, beautiful day in the Pacific Northwest when the volcano sent a plume of smoke and ash into the sky, flattening trees for more than 200 square miles.
"I just saw so much debris and dirt and mudflow and downed trees...just this incredible surging of material," Erickson said.
Jesse Hagerman was a rescue helicopter pilot with the National Guard. He said from the sky in Longview, Washington, you could see the whole column of smoke and ash -- "it was up 60,000 feet in the air."
"It was pretty unbelievably awesome," he said.
Hagerman said he picked up quite a few people near the site and remembers some of those flights were "like flying blind."
"Without a doubt it was one of the most interesting times of life," he said. "How many people have worked on an active volcano, especially when there`s so many unknowns?"
The eruption killed 57 people. At the time, it was described as the most violent volcanic eruption in 32,000 years and triggered the largest landslide in recorded history.
"I can`t forget it. I can`t forget the people that I encountered that I wrote stories about. How can I forget something that is imprinted on my brain?" Erickson said.
Erickson's book is covered with photographs that he took to mark the moment in history.
"I think it was a wakeup call for Washington state and scientists as well to be prepared," he said.
Erickson has a piece of advice: don't rely on technology to store those memories.
"Write down your memories," he said. "You can use them later."
Mount St. Helens is one of five active volcanoes in Washington state, along with Mount Adams, Mount Rainier, Glacier Peak, and Mount Baker. Washington state is home to a fourth of all the active volcanoes in the United States.