Mare's Tail Sunset

Mare's tail clouds (cirrus uncinus) are illuminated by the setting sun in this view of the northwest sky around 8:45 PM on June 12, 2010. I shot this image from a Sam's Club gas station on Blairs Ferry Road in Cedar Rapids, Iowa following a visit to the town of West Union earlier in the day. Cirrus uncinus is derived from Latin meaning "curly hooks." This type of cloud occurs at very high altitudes in cold and unstable layers and usually heralds the approach of precipitation--in this case from a thunderstorm--two days later.