Investigations of strange, linear features on Mars (AKA playing with dry ice blocks in the Utah desert)

Comparative geomorphology is a standard and highly useful approach in determining the origin of features seen on planetary surfaces. However, this approach sometimes can point interpretations into the wrong direction - the specific and sometimes highly unique conditions found on another planet cannot be neglected in the analysis! In particular, long, narrow grooves found on the slopes of martian sand dunes have been cited as evidence of liquid water via the hypothesis of melt-water initiated debris flows.