formation of a hanging valley

Before

• snow accumulates 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 with accumulated snow compressed into neve then ice

• glaciers flow downhill due to gravity/weight

• tributary glaciers fill tributary valleys

During

• plucking occurs when ice freezes onto bedrock pulling loose rocks away from the sides, making them steeper

• abrasion occurs when the angular rock embedded in the ice grinds the base, making it deeper

• former interlocking spurs may be cut off by the glacier as it flows downhill leaving truncated spurs and steep valley sides

After

• hanging valleys form as tributary glaciers have less power to erode and so form smaller valleys which are left ‘hanging’ above the main valley.

• rivers that flow in hanging valleys often descend to the main valley as waterfalls.

• an example is Grisedale valley in the lake district.