In 1958, dendrochronologist Terah Smiley studied tree-ring data from several beams of the 100 room Wupatki Pueblo, located 15 miles northeast of Sunset Crater, near Flagstaff, Arizona. The purpose was to determine the year and duration of a massive eruption, and concluded it occurred during the winter of 1064-1065 AD. As a result, a date of 1064 AD for the Sunset Crater eruption became accepted in both the geological and archaeological record. Later studies using a variety of chemical assays and detailed tree-ring morphology indicate that this date is likely inaccurate. Evidence now suggests that Sunset Crater most likely erupted in the mid-to-late 1080s AD.
Why is this significant to the Chaco Anasazi? The Sunset Crater eruption site is only 200 miles from Chaco as the raven flies. A dramatic cloud of ash and darkened skies would have had serious consequences on the growing season, shortening it with colder temperatures. This would have a negative effect on the wellbeing of the Chacoans and their psyche, as well. By moving the date of the eruption to the mid-1080s, the drama continues as this segues into the worst drought of the 11th century, with remarkably dry summers in the 1090s. How did the Chacoans respond? Around 1100, they started construction on 5 massive structures: Casa Chaquita, New Alto, Kin Kletso, Wijiji, and Tsin Kletzin. Were they trying to appease the gods with new construction honoring the great spirits? If they were, perhaps it worked, from 1100-1130 both the summer rains and annual rainfall were well in excess of long term averages, and the 5 new buildings were completed during this time. Three of the new buildings were slightly different; they were built with the “McElmo Phase” style of masonry, which had open plazas, versus the previously seen Chacoan style, with subdivided rooms, arc-shaped barriers, and enclosed plazas. What drove these changes, and were the changes related to the environmental phenomenon of the times? Again, it’s unknown, leaving us to draw intelligent conclusions based off of what we do know.
One of the striking features of Chaco is the dominating sky. With few trees or other impediments to the view, the sky feels omnipresent. When you combine the lack of horizon while actually in the canyon proper, and the high cliff walls, there is a “cocoon” sensation. Each edge of the canyon you see, even through the Fajada or South Gaps, looks like the edge of the world. At night, the lack of surrounding light pollution leads to spectacular stargazing. Planets and stars pierce the night sky like diamond needles. The rising of the moon is dramatic and arrives on stage like a movie star making a grand entrance.