Which forms of precipitation can contribute to glacier growth besides snowfall?

While snowfall is the primary source of mass for glaciers, several other forms of precipitation and processes contribute to their growth. These include:

• Hoarfrost: Formed by the direct condensation of ice from water vapor onto the glacier surface.1
• Rime: Created when supercooled water droplets freeze upon striking the glacier's surface.1
• Hail: Solid precipitation that adds mass to the glacier.1
• Rain and Meltwater: The freezing of rain or liquid meltwater can contribute to glacier mass, particularly when it refreezes within the snowpack or at the base of the glacier.12
• Avalanching: The accumulation of snow that slides onto the glacier from adjacent slopes also serves as a significant source of mass.1

These processes are part of the glacier's accumulation, which must balance against ablation—the loss of mass through melting, runoff, or calving—for a glacier to maintain its size or grow.1