In which zone does increased evaporation and melting exceed snowfall at lower elevations?

The zone where increased evaporation and melting exceed snowfall at lower elevations is known as the zone of ablation. This area is characterized by a net loss of ice due to processes such as melting, sublimation, and calving. In contrast to the zone of accumulation, where snow and ice are added to a glacier through precipitation and compaction, the zone of ablation represents the lower elevation on glaciers and ice sheets where conditions lead to a reduction in ice mass.

In this zone, the balance between snow accumulation and ice loss tips towards melting and evaporation, especially during warmer months when temperatures rise. This is crucial for understanding glacial dynamics and the response of glaciers to climate change, as a significant loss of ice in the zone of ablation can lead to a retreat of the glacier.

The equilibrium line, on the other hand, is the boundary between the zone of accumulation and the zone of ablation, marking the altitude at which the amount of snow accumulated in winter equals the amount of ice lost in summer. Crevasses are deep cracks in glaciers caused by differential movement and stress, not directly related to the balance of accumulation and ablation.