May 18, 2015 marks the 35th anniversary of Earth’s largest terrestrial landslide in historical times—a result of a restless volcano and a uniquely violent eruption. The top of Mount St. Helens plowed into Spirit Lake, throwing water 860 feet above lake level, a great inland tsunami. A ground-hugging hot surge sped across valleys and ridges, killing dozens of people and nearly all other life as it leveled 234 square miles of forest. An extraordinary natural phenomenon—a vast cloud—rose 19 miles and mushroomed, plunging much of Washington into ashen blackness darker than night as it spread across the state.

Part of a team studying volcanoes in the Cascades, Richard Waitt was one of the first United States Geological Survey researchers to arrive following the mountain’s early rumblings. Not long after the devastating events he met a couple who had barely outraced a searing ash cloud. Listening to their story, he realized that people who were even fleetingly in or just outside the eruption-leveled forest observed processes that a geologist later scrutinizing deposits couldn’t know.   He began interviewing other witnesses and eventually collected hundreds, often making repeated visits to gather additional details, correct errors, and resolve discrepancies.

Two that Waitt spoke with were Jim Scymanky and Mike Hubbard. Scymanky, about twelve miles northwest, was logging a north slope above Hoffstadt Creek. “Rocks zinged through the woods, bouncing off trees, then the tops of trees snapped off…it got hot right away, then scorching hot and impossible to breathe…I was being cremated, the pain unbearable.” Mike Hubbard was farther out—sixteen miles northwest near Green River. “I was on my knees, my back to the hot wind. It blew me along, lifting my rear so I was up on my hands…It was hot but I didn’t feel burned—until I felt my ears curl.”

Along with interviews, the author tapped numerous other primary sources—legal depositions, personal diaries, geologists’ field notes, radio logs, and police records. Newspaper stories and even sun shadows on photographs revealed additional intricacies. At first Waitt sought only to document the eruption’s natural processes, but these descriptions and remarkable personal experiences seemed inextricably intertwined. “Observations are valid to science only if place and time are known, and those elements were clarified by details of the adventure stories,” says Waitt. “Only together did they make a powerful and readable science story.” A meticulous scientist with intimate knowledge of Mount St. Helens, he is uniquely qualified to merge an accurate chronicle of events with the related science, and he brings it all together in his Washington State University Press book based on those accounts, In the Path of Destruction: Eyewitness Chronicles of Mount St. Helens.