It was an explosion that created Sunset Crater in northern Arizona. Another proposed explosion almost led to its demise.
Sometime toward the end of the 11th century about 20 miles north of present-day Flagstaff, the ground likely shook for weeks or months, with earthquakes becoming increasingly frequent. Then, one day, the earth opened and spewed volcanic ash as hot as 2,000 degrees Fahrenheit high into the air. The ash plume was so large that it might have been visible from high points as far as current-day Palm Springs in California or Las Vegas. At night, the fountain of fiery embers and lava bombs could have been seen from southern Utah. The ash and steam triggered thunderstorms, and red-hot ash probably started forest fires. When the eruption ended, the volcano towered 1,000 feet above the valley floor.
The eruption of the volcano now known as Sunset Crater is the most recent in northern Arizona’s San Francisco Volcanic Field, which has been active for much of the past 6 million years. Of all the eruptions in the Southwest, it is also the only one that was indisputably witnessed by humans. Pithouse dwellings that had been built in the four centuries before the eruption were burned and buried under layers of ash before being excavated in the 1930s. Local Sinagua people used ears of corn to make imprints in cooling lava, perhaps as spiritual offerings. No human remains have been found buried in volcanic deposits, which could suggest that locals were able to evade the fate suffered 900 years earlier by the residents of Pompeii.
Still, the eruption profoundly altered the existence of the area’s rural communities. For the duration of the eruption, which might have lasted months, air quality in the vicinity of the crater deteriorated significantly. Near the crater, the thick layers of ash made farming temporarily impossible. People might have come back just a few years after the ash had settled, and less than a couple of centuries later, the area experienced a substantial population increase. While the large quantities of ash close to the volcano hampered farming productivity, the thinner ash layers farther from the crater actually improved soil quality, acting as mulch that retained moisture.
The region lost much of its population around the middle of the 13th century, but Hopi travelers, Havasupai hunters and others continued to pass through the region. In the 19th century, Navajo grazed their herds in the area. The crater remained important in local culture, and it is part of the oral histories of several area tribes, including Navajo, Apache, Hopi, Paiute, Zuni, Yavapai, Havasupai and Hualapai peoples to this day.
It was the famous explorer, John Wesley Powell, who named the volcano “Sunset Mountain” during one of his expeditions in the Southwest in 1892. The name was inspired by the colorful minerals — including gypsum, hematite and opal — deposited by the volcano’s hot springs and vapors near the top of the crater.
Despite the volcano’s scenic beauty and cultural significance, a movie crew in the late 1920s planned to blow it up to create an avalanche. By then, the American West novels of Zane Grey were bestsellers, and they were routinely turned into black-and-white silent motion pictures. At the time, the vast majority of movies were filmed in Los Angeles and New York, but Grey thought the setting was as important to the movies inspired by his books as it was to the books themselves, so he pushed for some of these movies to be shot on location in Arizona (one, “The Water Hole,” was filmed in 1928 in part at Navajo National Monument, which had been established a couple of decades earlier).
For the movie adaptation of Grey’s 1928 “Avalanche” novel, a realistic location was not the only requirement — also crucial to the movie producers was a real-life avalanche depicting the story’s dramatic turning point. According to the book’s narrative (existing copies of the movie have been lost), two brothers feud over the love of a woman. One of them rides to a nearby gorge after a particularly fierce fight with his brother, only to be to be caught under a deluge of “rocks as large as cabins.”
“The section of rim wall, giving way, had started the whole slope below into a colossal avalanche,” Grey writes. “It was a brain-numbing spectacle: The vast green slope of cedar and piñon, of manzanita and oak, of yellow crag and red earth, had become a swelling, undulating cataract. It was beautiful, awe-inspiring. Only the cataclysmic sound rendered proof of its destructive force.”
When Jack sees his brother Verde badly hurt, he realizes the foolishness of their dispute and endeavors to save his dear brother.
The movie crew set their eyes on Sunset Crater, with its slopes of loose rock and ash, as the perfect location for the movie’s pivotal scene, and they planned to use dynamite to blow up part of the crater. When Harold Colton, the founder and director of the Museum of Northern Arizona, heard of the scheme, he was incensed. He quickly organized local opposition and petitioned the federal government to protect the volcano in perpetuity. His concerns were heard. On May 26, 1930, President Herbert Hoover, a one-time NPCA president, established Sunset Crater National Monument, one of a dozen national monuments Hoover created under the authority of the Antiquities Act. Sunset Crater was originally managed by the U.S. Forest Service, but it was transferred to the National Park Service in 1933 and renamed Sunset Crater Volcano National Monument in 1990.
The Avalanche movie ended up being shot elsewhere in the San Francisco Peaks, and the film’s climactic scene still captivated audiences, according to a 1929 review in the Healdsburg Tribune in California. “The most spectacular scene in the picture provides the crisis of the story,” the reviewer wrote. “A whole mountainside is shown in a great avalanche.”
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About the author
Nicolas Brulliard Senior Editor
Nicolas is a journalist and former geologist who joined NPCA in November 2015. He writes and edits online content for NPCA and serves as senior editor of National Parks magazine.