The presence of liquid water at and beneath frozen Alaskan sand dunes during the winter months suggests that liquid water could also be temporarily stable (or metastable) at frost-covered sand dunes on Mars.
A team of Earth and planetary scientists from Southwest Research Institute (SwRI) performed field studies of the Great Kobuk Sand Dunes, which serve as an Earth-based cold-climate “analog” to dunes on the Red Planet.
The team conducted fieldwork in Kobuk Valley National Park, Alaska, when the average daily surface temperature was -14.7°C. Geophysical data gathered by SwRI scientists strongly suggest that there is a perched layer of liquid water in the dunes occurring just below the seasonally frozen active layer.