Which conditions allow snow to accumulate long enough to form a glacier?

Glaciers form when the annual accumulation of snow, rime, and other forms of solid precipitation exceeds the amount lost to summer melting. For snow to persist and eventually transform into glacier ice, it must survive at least one melting season, at which point it is referred to as firn or névé.123

The transformation process requires specific conditions:

• Mass Balance: A glacier grows when there is a positive mass balance, meaning the accumulation of snow is greater than the loss through melting, runoff, or the breaking off of icebergs.4
• Densification: Over time, the weight of overlying snow compresses the accumulated layers. This process involves the rounding of ice grains, sintering, and recrystallization, which increases the density of the snowpack.23
• Temperature and Environment: The rate of this transformation depends heavily on temperature and wetness. In warmer, wetter environments, the transition from snow to glacier ice can occur in just a few years, whereas in cold, dry regions like the Antarctic plateau, the process may take thousands of years.21