The only terrain variation lies at the south end of the city, where Lost Draw carves a channel that runs across the entire county. Lost Draw formed over 10,000 years ago at the end of the last ice age, when the climate of the area was much wetter. When the vast glaciers of the north retreated, they left numerous dry river channels crisscrossing the Llano Estacado. When settlers during the 1800s ventured across this area, they often went into these channels expecting to find water, but unless significant rains had occurred recently, their search was in vain, with many of the parties becoming "lost", hence the name, Lost Draw.