Explain glacier mass balance

Glacier mass balance is a tricky concept to understand without understanding the accumulation and ablation first. Accumulation is when a glacier is gaining mass normally from snowfall which has been compressed. Whereas, ablation is when snow or ice which make up a glacier are lost through different processes such as meltwater, water vapor and calving. Therefore, the glacier mass balance is the annual cycle of both these processes. During the colder months (ie winter in the northern hemisphere) there is more accumulation on a glacier than there is ablation so there is a positive balance and the glacier gains overall mass ( I can also explain this using a diagram). This is because it is colder hence, there will be more snowfall and less melting. Equally, in the warmer seasons there is more ablation than there is accumulation so the glacier's overall mass decreases. We then can conclude that the maximum glacier mass is in spring and the minimum is in the autumn.