The private pilot reported departing the airport in "challenging wind and [thermal] conditions." An automated weather reporting facility on the airport reported winds 50 degrees from runway heading at 11 knots gusting to 19 knots. After six successful touch-and-gos, the pilot entered the traffic pattern for a seventh approach. While turning base to final the pilot experienced a loss of aircraft control and impacted terrain. The pilot reported that dust devils were "prevalent in the area at that time."