1) Glaciers retreat due to less snowfall in the accumulation zone and rising temperatures in the ablation zone caused by global warming. 2) The glacier has accumulated in the u-shaped valley it resides in, carrying debris like moraines. 3) Glacial troughs form as the mass of ice abrades and erodes the valley walls and floor over time, creating a characteristic u-shape.

1. Ice On Land

2. 6AIII- Suggest reasons for the retreat of a
glacier
• Caused by less precipitation (less snow) in the
zone of accumulation which could lead to a
decrease in snow and ice. (2 marks)
• Rising temperatures (caused by global
warming) at lower altitudes in the zone of
ablation could lead to it’s retreat to higher
altitudes. (2 marks)

3. Describe Characteristics of the Glacier
• The glacier is white and has accumulated the
whole of the valley. (1 mark)
• The valley it’s housed in is a u-shaped valley
formed through abrasion. (1 mark)
• The glacier is carrying small and large pieces
of debris (lateral and medial moraines) (1
mark)

4. 6C- Explain the formation of a glacial
trough
• A glacial trough is a u-shaped valley. (1 mark)
• The mass of snow and ice made its way down
the valley, it would slowly abrade and erode
away the edges and bottom. This consequently
formed a u-shaped valley. (3 marks)

5. 6D- Explain why avalanches occur
• Avalanches are a sudden fall and dislodgement of snow that
tumbles down a mountain at vast speeds. (1 mark)
• This can be caused by natural events or man made events
and actions. (1 mark)
• Excessive snow can cause an imbalance in the existing
snow on the cornice.
• Volcanic or earthquakes activity can cause vibrations in the
snow.
• Deforestation, e.g. for ski slopes. Can lead to avalanches as
the trees act as a barrier that can support the snow and
prevent it from sliding.
• Winter sports like skiing can cause vibrations that can cause
the snow to dislodge, causing an avalanche.