Corrie

• Glaciers move downhill due to gravity.
• Glacier formation includes snow accumulating in north facing hollows when more snow falls in winter than melts in the summer.
• North facing slopes are more shaded, so snow lies longer.
• Plucking occurs when ice freezes on to bedrock, pulling loose rocks away from the backwall.
• An example of a corrie is Red Tarn.
• Friction causes the ice to slow down at the front edge of the corrie, allowing a rock lip to form which traps rain water.
• freeze thaw weathering occurs when water in cracks in the rock freezes, expands and contracts, weakening the rock until fragments break off.
• The weight of the glacier pushes down causing rotational sliding, which over deepens the hollow.
• Abrasion occurs when the angular rock embedded in the ice grinds the hollow.