Gullies on Mars form during the winter, fluidized by carbon dioxide frost, so we monitor these sites for activity throughout the year.

This mid-winter scene is almost completely frosted over the pole-facing slope within the shadow.

ID: ESP_062894_1435
date: 27 December 2019
altitude: 252 km

https://uahirise.org/hipod/ESP_062894_1435
NASA/JPL-Caltech/UArizona
#Mars #science #NASA