The mystery is solved. I believe I know why the ancient Southwest cliff dwellers left their homes.
We first visited Mesa Verde in 1981. There were many possible reasons given why these people, now referred to as Ancestral Puebloan People, suddenly left their homes. A Park Service publication says: Several theories offer reasons for their migration. We know that the last quarter of the A.D. 1200s saw drought and crop failures—but these people had survived earlier droughts. Maybe after hundreds of years of intensive use the land and its resources—soils, forests, and animals—were depleted. Perhaps there were social and political problems, and the people simply looked for new opportunities elsewhere. We were involved in political life in 1981, and I wondered if some messianic leader led them away.
Navajo National Monument: Betatatkin Dwellings
We found the same situation in other parks where Ancestral Puebloan people lived: Navajo National Monument; Montezuma Castle, Aztec Ruins, and Hovenweep.
Then on October 25th, our local PBS station showed an episode of NOVA called Killer Volcanoes.
Archaeologists excavating a London cemetery found over four thousand people buried in mass graves, just large pits. That means a lot of people died in a very short time. The deaths came about a century before the Black Death struck Europe. Also, a historical record showed extreme winter weather in 1257-58 accompanied by torrential summer rains. 15,000 people, thirty percent of London’s population, died.
Further records found massive famine in that same period across Europe and as far away as Japan.
When Mount Tambora in Indonesia erupted in 1815, it was followed by “the year without summer.” New York experienced snow in June 1816.
When a volcano explodes, it puts minute droplets of sulfuric acid in the atmosphere which reflect the warming sunlight. It seemed logical that there was a volcanic explosion in 1257.
But no record of the explosion was found.
Examination of ice cores taken from both polar poles found high concentrations of sulfuric acid during that period and microscopic volcanic ash that matched. It turns out each volcanic explosion has its own signature ash. Since the gas and ash covered the entire earth, the eruption must have been near the equator.
Some thirty years later, a geologist took on the quest. He examined satellite images of volcanic craters in Indonesia which has 129 active volcanoes. He found the island of Lambok with a four mile-wide crater near Mount Rinjani. Pumice deposits on the island were 120 feet deep. [The pumice in which Mount Vesuvius buried Pompeii is only 16 feet deep.]
An Indonesian record was found mentioning avalanches off Mount Rinjani and the collapse of Mount Samalas. No one had heard of Mount Samalas.
The geologist and his colleagues came to the conclusion that Mount Samalas, a thousand feet higher than its neighbor Mount Rinjani, had disappeared in “possibly the most powerful volcanic eruption in recorded history.”
Carbon dating of ash in the pumice and comparisons with the polar samples confirmed the explosion was the cause of the worldwide famine that began in 1258.
The program did not mention the Ancestral Puebloan people, but it immediately occurred to me the timing was right.
The Ancestral Puebloan People may have experienced drought before. But the exceptionally harsh weather and famine in 1257-1258 must have been horrific to a stone-age culture. They might even have concluded their gods were unhappy. I believe it is why these people migrated over the next decades to where they became the ancestors of the modern Hopi, Zuni and other Puebloan groups in Arizona and New Mexico.
Am I right? More than ever, I am interested in your thoughts and opinions.
When you visit that area, ask what the rangers have to say.