A process that allows water to remain liquid below 0 °C. It is associated with basal water flow through subglacial overdeepenings; as the subglacial melting point changes in response to changing pressure, water may become supercooled, and freeze, but if the adverse bed slope is steep enough, the heat generated will not be enough to match the changed pressure melting point, and it will become supercooled. For more details, see Hooke (1991) Geol. Soc. Amer. Bull. 103 and Alley et al. 1998 J. Glaciol. 44. Alley et al. (2003) Nature 424 view supercooling as a key link between glacier dynamics, basal ice formation, and subglacial landform evolution. For field evidence of glaciohydraulic cooling, see Hooke and Pohjola (1994) J. Glaciol. 40 and Lawson et al. (1998) J. Glaciol. 44.

Glaciohydraulic cooling is associated with subglacial deformation (Echelmeyer and Zhongxiang (1987) J. Glaciol. 33), and ice creep at crystal boundaries (Wolff and Mulvaney (1988) Ann. Glaciol. 11). Cooke et al. (2006) PPG 30, 5 review recent work on glacial supercooling. Knight (2006) PPG 30, 5 suggests that the significance of glaciohydraulic supercooling may have been overestimated.