The presence of basal meltwater depends on both bed temperature and other factors. For instance, the melting point of water decreases under pressure, meaning that water melts at a lower temperature under thicker glaciers. This acts as a "double whammy", because thicker glaciers have a lower heat conductance, meaning that the basal temperature is also likely to be higher. Bed temperature tends to vary in a cyclic fashion. A cool bed has a high strength, reducing the speed of the glacier. This increases the rate of accumulation, since newly fallen snow is not transported away. Consequently, the glacier thickens, with three consequences: firstly, the bed is better insulated, allowing greater retention of geothermal heat.
The presence of basal meltwater depends on both bed temperature and other factors For instance the melting point of water decreases under pressure meaning that water melts at a lower temperature under thicker glaciers This acts as a "double whammy" because thicker glaciers have a lower heat conductance meaning that the basal temperature is also likely to be higher Bed temperature tends to vary in a cyclic fashion A cool bed has a high strength reducing the speed of the glacier This increases the rate of accumulation since newly fallen snow is not transported away Consequently the glacier thickens with three consequences firstly the bed is better insulated allowing greater retention of geothermal heat