nivation

Nivation is a geomorphological process that occurs in cold environments, particularly at the base of snow patches. It involves a combination of physical and chemical weathering that breaks down rock and soil material. The process begins with snow accumulation, which insulates the ground beneath during winter. As the snow melts in spring and summer, meltwater percolates through the soil and any existing cracks in rocks. This water can freeze and thaw repeatedly, a process known as frost weathering, which widens cracks and dislodges rock fragments.

Additionally, the meltwater can carry dissolved organic acids from decaying vegetation trapped within the snow. These acids contribute to chemical weathering, dissolving minerals in the rock and soil. The movement of snow also plays a role, as it can abrade exposed rock surfaces. Over time, these combined actions lead to the formation of a hollow or niche at the base of the snow patch. This feature is known as a nivation hollow. These hollows can enlarge and deepen with continued nivation, and if they become large enough, they can evolve into larger landforms like cirques, which are characteristic features of glaciated mountain landscapes. Nivation is thus considered a pre-glacial process, contributing to the initial stages of landform development in periglacial and alpine environments.