Nature Geoscience, Published online: 07 October 2026; doi:10.1038/s41561-026-02109-8

Water-ice clouds are common across the Solar System, but their formation typically requires pre-existing dust particles to coax water vapour into ice. Atmospheric simulations now suggest that gravity waves over a Martian volcano can bypass the need for dust, generating ice clouds through spontaneous nucleation of water vapour.