Net mass balance

Glacier mass balance data from the World Glacier Monitoring Service

At any point on the glacier, there will usually be some mass gained in the winter and some mass lost in the summer. The difference between these quantities is the net mass balance. This will vary with elevation on the glacier, as both the accumulation and ablation components vary with elevation.

The point on the graph where the net mass balance equals zero is known as the equilibrium line altitude (ELA).