When I got back to the campground on Sunday evening, I found that a horrible wind storm had blown my tent away and during the night it snowed about three inches. I managed to get my tent back together, and in the morning we looked at the canyon in the snow. Fajada Butte was particularly dramatic. Fajada Butte is a dominant visual feature in Chaco Canyon. Near its top is the famous astronomical device which consists of spiral stone carvings and three stone slabs. Daggers of sunlight touch the spirals at different locations at the time of the solar solstices and equinoxes. The device also apparently uses moonlight to measure the lunar cycle. Some theorize that the measurement of time by the Chacoans was less about governing agricultural, because there are a number of unique microclimates in the area requiring different planting cycles. They argue that the measurement of time was more likely needed to carefully maintain the ceremonial cycles.