Carbon dioxide frost from the past winter still thickly blankets this terrain imaged in early Martian spring. Dark blob-like surface markings show the initial hints at the coming defrosting and soon these dark marks will cover the whole scene before the frost dissipates entirely in summer.

Of special interest in this image are the gullies that are visible at regular intervals leading from the tops of the high-standing mesas to the lower terrain. During defrosting, these gullies will become active and they will host flows of a slurry of frost, gas, and underlying rocky material. The cold carbon dioxide frost temperatures mean that no liquid water is involved.

Repeated observations of these sites allow us to understand these seasonal effects on Mars and comparison to other years give us valuable insight into the variability of Mars” current climate.

ID: ESP_091519_1090
date: 3 February 2026
altitude: 251 km

https://uahirise.org/hipod/ESP_091519_1090
NASA/JPL-Caltech/University of Arizona
#Mars #science #NASA