text: Pat Ruthenberg last spoke with her brother, David A. Johnston, a week before he was killed in the 1980 eruption of Mount St. Helens.
  
  "He quite understood the danger," Ruthenberg recalled, over coffee in the kitchen of her Oak Lawn home one recent morning. "He was happy to be there and to have the opportunity to study but he was quite concerned about public safety and the stuff that goes with it."
  
  With the help of her longtime friend and freelance writer, Melanie Holmes, who is currently working on a book about Johnston, Ruthenberg recounted the event that took the life of her older brother, a 1967 graduate of Richards High School, but shed valuable scientific light on pyroclastic blasts. The catastrophe has become the impetus for an upcoming PBS special titled, "We'll Meet Again."
  
  As she chatted with the 30-year-old Johnston on that Mother's Day Sunday nearly 38 years ago, Ruthenberg had no idea the fate that awaited her only sibling, nor could she foresee the countless lives his safety efforts would save.
  
  Among those who praised those efforts was Mindy Brugman, a graduate student doing research on the mountain at the time.
  
  Chris Sweda, AP
  
  On May 18, 1980, David Johnston, one of a team of U.S. Geological Survey scientists studying the Mount St. Helens, was killed when it erupted.
  
  On May 18, 1980, David Johnston, one of a team of U.S. Geological Survey scientists studying the Mount St. Helens, was killed when it erupted.
  
  (Chris Sweda, AP)
  
  As seismic activity increased throughout the spring on what had been a longstanding dormant volcano, Johnston and the United States Geological Survey convinced authorities to close Mount St. Helens to the public. Just prior to this, Mount Baker, also in the Cascades range, had been closed off for fear it would erupt. That didn't happen, so the closing of Mount St. Helens was met with criticism and outrage, Holmes said.
  
  But Ruthenberg said her brother was fearful of what Mount St. Helens was capable of doing. "He likened it to lighting a fuse to a dynamite keg but you don't know how long the fuse is."
  
  Johnston sent Brugman and other students to a safe zone just before the blast. The volcanologist, who studied the chemical makeup of gases, stayed behind to record data and man an observation post that was more than five miles north of the mountain, Holmes said.
  
  The fuse burned exactly one week. At 8:32 on the morning of May 18, Mount St. Helens erupted with a force of "1,500 Hiroshima atomic bombs," according to smithsonianchannel.com. Rock and hot gas shot from the mountain at 400 miles per hour, the film states.
  
  Though many scientists thought the volcano would erupt vertically, it exploded laterally, killing 57 people, Johnston among them, and sending ash across 11 states.
  
  It has been widely reported that Johnston had just enough time to transmit "Vancouver! Vancouver! This is it!" before he was swept away.
  
  Had they not closed the area to the public, Holmes said, the death toll would have been much higher. "They learned a lot from the work that David and other scientists who stayed behind did," she said.
  
  On May 18, 1980, Mount St. Helens in Washington state erupted, killing 57 people, blasting more than 1,300 feet off its peak and raining volcanic ash for miles around. A magnitude-5.1 earthquake hit at 8:32 a.m. local time, causing the volcano's north flank to collapse, which triggered the largest landslide in recorded history. That set off powerful explosions that sent ash, steam, rocks and volcanic gas upward and outward. The lateral blast scorched and flattened about 230 square miles of dense forest. Ash rose over 80,000 feet and rained down as far as 250 miles away in Spokane.
  
  In the years that passed, both Ruthenberg, her late parents, Alice and Thomas Johnston, and Holmes visited the site of the eruption as well as the many memorials that stand in Johnston's name. But they had not met with Brugman.
  
  Last fall, the PBS series, produced by Blink Films in partnership with AnnCurry Inc., brought Brugman to Chicago to meet Ruthenberg. The episode was filmed at a park near Logan Square, Ruthenberg said.
  
  "We'll Meet Again," hosted by Curry, revisits events in history through the stories of those who experienced them and connects people whose lives intersected at pivotal moments.
  
  The series starts Jan. 23 with "Children of WWII." "Rescued From Mount St. Helens" airs Jan. 30. Subsequent episodes will focus on the lost children of Vietnam, the Sept. 11 terrorist attacks, the civil rights movement and gays in America.
  
  In the Mount St. Helens feature, Brugman meets with Ruthenberg to tell her how Johnston, her team leader, saved her life.
  
  Ruthenberg said when the show's production team first reached out to her last year about filming, she said she was hesitant to participate. So often since the disaster, she said, false or misleading information had been published or produced about her brother.
  
  Johnston was "a kind man who loved photography and running but mostly his work," she said.
  
  AP
  
  On May 18, 1980, Mount St. Helens erupted, sending a plume of smoke and ash skyward. David A. Johnston, a scientist who grew up in Oak Lawn, was among the 57 killed in the disaster.
  
  On May 18, 1980, Mount St. Helens erupted, sending a plume of smoke and ash skyward. David A. Johnston, a scientist who grew up in Oak Lawn, was among the 57 killed in the disaster. (AP)
  
  Although the scientific community quickly recognized the value of his research, giving scientific merit to his work on pyroclastic gases, pop culture has not been as kind, she said.
  
  One hastily made film depicted him as "a conspiracy theorist renegade who was careless," she said. "He was the opposite of that," she said.
  
  "I went to my 50th grammar school reunion and two guys I grew up with made reference to David from that horrible movie," she said. "It was so hideous. There's no other way to describe it. There was a lot of outrage among the scientific community about it too."
  
  In other cases, she said, local journalists questioned why he didn't heed his own advice to get off the mountain or commented that because Johnston had been a runner, perhaps he opted to stay behind thinking he could outrun the eruption.
  
  "That's ridiculous," Ruthenberg said.
  
  "And unfair," Holmes added. "He was doing his job."
  
  Holmes, who lives in Palos Park, said her book, which is in the final editing stages at University of Illinois Press, carries the working title "David A. Johnston: A Mount St. Helens Hero."
  
  "Because he was a hero," she said.
  
  Ruthenberg agrees.
  
  Meeting with Brugman, she said, only reaffirmed what she already knew about her brother, who graduated from the University of Illinois before heading to University of Washington to pursue his doctorate.
  
  Ruthenberg, a now-retired physical therapist, named her oldest son after Johnston.
  
  "I want people to know how brilliant he was. He was a very modest man. Very fun, humorous. He was very thoughtful. Very concerned about people," she said.
  
  "He was smart in the way that he worked really hard to learn more about things he didn't understand," Holmes added.
  
  Ruthenberg recalled how Johnston once signed up for a math class that was not required. "He wanted to know more, he wanted to be better at it, he wanted to feel more confident with it," she said.
  
  Simon Harries/Blink Films
  
  Pat Ruthenberg, left, met with Mindy Brugman for the first time recently to film an episode of the PBS series "We'll Meet Again." Brugman credits Ruthenberg's brother, scientist David A. Johnston, with saving her life by sending her off Mount St. Helens, where she was studying, just before the volcano erupted.
  
  Pat Ruthenberg, left, met with Mindy Brugman for the first time recently to film an episode of the PBS series "We'll Meet Again." Brugman credits Ruthenberg's brother, scientist David A. Johnston, with saving her life by sending her off Mount St. Helens, where she was studying, just before the volcano erupted. (Simon Harries/Blink Films)
  
  The women also describe a shy, humble man who'd often feel faint before giving speeches. Growing up in first Hometown and then Oak Lawn, she said, he'd been a Boy Scout and quickly developed a deep love for science and nature. He went away to college intending to be a journalist but an introductory class in geology changed his path.
  
  "He had a couple of girlfriends," Ruthenberg recalled. "One was a student when he was teaching in graduate school.
  
  After his death, his mom, an editor for the Southtown Economist, and his dad, an engineer for People's Gas, commissioned an Oak Lawn artist to make a painting from a photograph of their son. That painting hangs at Cascades Volcano Observatory in Vancouver, Washington.
  
  The Johnston Ridge Observatory, named for the fallen scientist, is located close to the ridge where he died.
  
  And, Holmes added, a seven-pound volume explaining the Mount St. Helens catastrophe is dedicated to Johnston.
  
  In the intro it states: "The volcano-monitoring effort of which Dave was part helped persuade the authorities first to limit access to the area around the volcano, and then to resist heavy pressure to reopen it, thereby holding the May 18 death toll to a few tens instead of thousands."
  
  It also describes Johnston as "an exemplary scientist," who had an "infectious curiosity and enthusiasm."
  
  "David is a local hero out west," Holmes said.
  
  She recalled a story told to her through an email. A junior high-age boy chose to complete an assigned report on his hero by dressing up as Johnston. Holmes said the student was asked to give the presentation hundreds of times.
  
  And Ruthenberg recalled meeting a man from Seattle while on vacation in Disney World. "He knew all about David," she said.
  
  "He was a good guy," Ruthenberg said. "And it was important for him to be a good guy."
  
  Gary Middendorf/Daily Southtown
  
  Author Melanie Holmes, right, is currently working on a book about the life and work of David Johnston, brother of Pat Ruthenberg, left. David was a geologist from Oak Lawn who killed while studying Mount St. Helens during its eruption in 1980.
  
  Author Melanie Holmes, right, is currently working on a book about the life and work of David Johnston, brother of Pat Ruthenberg, left. David was a geologist from Oak Lawn who killed while studying Mount St. Helens during its eruption in 1980. (Gary Middendorf/Daily Southtown)