"Superhot" or "supercritical" geothermal resources contain aqueous fluids at temperatures in excess of the critical temperature of water (374°C). Such conditions are encountered just above the magma body that drives conventional high-enthalpy geothermal systems (Figure 1) but have only recently intentionally been drilled into in the course of the Iceland Deep Drilling Project, IDDP. The two IDDP wells encountered 450°C at Krafla and likely >500°C at Reykjanes.

Drying of porous media is ubiquitous in various hydrologic and engineering processes ranging from evaporation from terrestrial surfaces to drying of food, building materials, pharmaceutical products, and preservation of historical buildings. Water evaporation from soil, arguably the porous medium ‘par excellence’, plays an important role in water management, land-atmosphere interactions, soil salinization, vegetation and crop production, biodiversity and ecosystem functioning. Therefore, it is important to have a clear understanding of the processes controlling water evaporation from porous media.