refreezes

Refreezes refers to the transition of liquid water to solid ice after a period of melting, driven by a fall in temperature below the freezing point. It is a common aspect of freeze-thaw cycles in cold climates and influences natural environments as well as human infrastructure.

On roads, pavements, and other surfaces, daytime meltwater can refreeze overnight, forming a slick ice layer known as black ice. Refreezing also occurs on rooftops, walkways, and airport runways, where it affects safety, maintenance, and operations.

In snow and ice systems, refreezing describes water from melting snow or rain infiltrating the snowpack and re-freezing when it encounters colder pockets. This creates ice lenses and crusts, altering snow permeability, stability, and surface albedo, with implications for avalanche risk and thaw dynamics.

In glaciology and cryospheric science, refreezing can occur within firn or along ice pores, contributing to internal refreezing of liquid water in contact with cold ice. It affects the thermal structure of ice bodies and can form higher-density ice layers.

Environmental and safety implications: refreezes affect surface roughness, water pathways, and ecological conditions. Forecasting and mitigation use weather data, deicing agents, and physical removal to manage hazards on roads and infrastructure.