degelo

Degelo is the process by which ice or frozen ground and surfaces turn into liquid water as temperatures rise above the freezing point. In many languages, degelo refers to thawing, whether of natural ice, snow, permafrost, or frozen foods.

In natural environments, degelo occurs when heat energy exceeds the latent heat of fusion for ice. Factors include air temperature, solar radiation, wind, humidity, snow cover, and the thermal properties of soil and rock. Seasonal degelo produces snowmelt and runoff; in polar regions, permafrost thaw alters ground stability and hydrology; glacier melt contributes to sea level change. Degelo can release stored greenhouse gases from soils and ice-rich sediments, particularly methane from thawing permafrost.

In human contexts, degelo is monitored to manage water resources, flood risk, and infrastructure. It also refers to food defrosting, where frozen items are warmed to a safe, usable state for cooking, typically through air, water, or microwave methods, while maintaining safety and quality.

Measurement and modeling rely on temperature data, degree-day factors, precipitation, and remote sensing to estimate melt rates and active-layer depth. Climate change is intensifying degelo in many regions, with cascading effects on ecosystems, water availability, and carbon release.

See also: thaw, melting, permafrost, glacier melt, defrosting (food).