David A. Johnston

David Alexander Johnston was a prominent American volcanologist with the United States Geological Survey (USGS). A volcanologist is a scientist who specializes in studying volcanoes and volcanic activity. Johnston was particularly skilled at analyzing volcanic gases to understand how they relate to eruptions. He believed that monitoring these gases could help predict when a volcano might erupt. This work was vital for protecting the public from natural disasters. His dedication and positive attitude made him highly respected by his colleagues in the scientific community.

Johnston’s scientific journey began with a change in focus during his college years. He originally planned to study journalism at the University of Illinois Urbana-Champaign. However, an introductory geology class sparked a new passion for the Earth. He graduated with highest honors in 1971 and began studying extinct volcanoes. He explored the San Juan volcanic field in Colorado and ancient volcanic remains in Michigan. These early studies helped him reconstruct the eruptive histories of old volcanic sites. This foundation prepared him for the much more dangerous work of studying active volcanoes.

As his career progressed, Johnston became an expert in the chemistry of volcanic activity. He focused on how magmatic volatiles, or gases trapped in magma, behave before an explosion. During his Ph.D. work at the University of Washington, he studied the Augustine Volcano in Alaska. He discovered that the way pyroclastic flows—fast-moving clouds of hot ash and gas—were deposited changed over time. He also found that magmas contained high amounts of water, chlorine, and sulfur. He even studied how the mixing of different types of magma could trigger an eruption.

In early 1980, Mount St. Helens in Washington began showing clear signs of unrest. The mountain had been mostly dormant since 1857, but new activity started in March. Small earthquakes began rocking the area, signaling that magma was moving underground. By late March, the volcano was experiencing phreatic eruptions, which are explosions caused by steam. These eruptions sent plumes of ash and steam high into the air. The volcano was even erupting up to 100 times per day during this period.

A major sign of danger appeared on the mountain's north flank. A large bulge, known as a cryptodome, began to grow as magma pushed upward. This bulge was growing at a startling rate of 5 to 8 feet every day. Scientists used laser ranging and tiltmeters to measure these changes in the mountain's shape. They also found high levels of sulfur dioxide gas in the crater. Johnston and the USGS team worked hard to monitor these changes to assess the risk to the public.

On the morning of May 18, 1980, the situation at Mount St. Helens turned catastrophic. Johnston was manning the Coldwater II observation post, located just north of the mountain. He was the first person to report the eruption, transmitting the urgent message, "Vancouver! Vancouver! This is it!" Shortly after, he was swept away by a lateral blast, which is a powerful explosion that moves sideways. Despite a thorough search, his body was never recovered. He remains one of only two American volcanologists known to have died in a volcanic eruption.

Today, Johnston's legacy lives on through science and various memorials. His work helped convince authorities to close the area around Mount St. Helens before the eruption, which saved lives. Two volcano observatories are named after him, including the Johnston Ridge Observatory. A memorial fund was also established at the University of Washington to support graduate research. His life and his final moments have been documented in many books and films. He is remembered as a scientist who was willing to take risks to protect society.