groundice

Ground ice refers to ice that forms within the subsurface of soils and rocks, occupying pore spaces or existing as discrete masses. It is a major component of permafrost and of periglacial environments, and it can occur in multiple forms, from small-scale pore ice to large buried ice bodies and ice wedges.

Common forms include pore ice, ice lenses, and wedges; buried ice may be remnants from former glacial ice preserved in sediments. These ice bodies can persist for long periods even as surface climates vary.

Formation mechanisms involve freezing of pore water and the movement of water within soils during seasonal temperature cycles. Segregation ice forms as unfrozen water migrates to freezing fronts, creating horizontal lenses; frost heave can generate vertical ice wedges in saturated sediments.

Ground ice affects ground stability and hydrology. Thawing ground ice due to warming induces thermokarst, surface subsidence, cracks, and landform change, with implications for infrastructure, land-use, and ecosystems. It also plays a role in regional methane release in some settings.

Scientists study ground ice using boreholes, thermal monitoring, ground-penetrating radar, electrical resistivity tomography, and remote sensing to map ice distribution and assess stability. Accurate mapping is challenging due to burial, variable sediment properties, and seasonal moisture changes.