Regelation

Regelation, melting of ice under pressure and refreezing when the pressure is removed. When compressed, ice changes into water; when temperature conditions are at or below 32°F (O°C), it freezes again when the pressure is taken off. A large rock on frozen water gradually sinks as the pressure melts the ice directly below it, but as the rock sinks the water refreezes around it. Glaciers undergo a slow process of regelation, melting and refreezing as they move along, in some cases pushing ice fields high up the slopes of mountains.