Nivation refers to a number of different processes involving the melting and refreezing of [snow]. It is used primarily in the fields of [glaciology] and [geology].

First off, nivation refers to the process of snow turning into solid [ice] by melting and refreezing into a more compact mass. This may happen very quickly (over one summer) or slowly, spending a long time passing through various degrees of [névé], depending on how much the snow melts.

Nivation may also refer to [erosion] and [weathering] to the ground under a [snowpack]. This weathering is due primarily to [freeze/thaw erosion] and [chemical weathering]. These processes may also encourage [mass wasting], such as [gelifluction] and [solifluction]. These take many years to cause any great damage, but snow may sit over a given spot for decades or centuries, and can do quite a lot of damage. These processes are necessary to get certain [periglacial] formations started, for example [cirque|cirques], which could not gain a foothold if nivation didn't get things started.

Nivation may also sometimes be used to refer to erosion caused by [meltwater] streams flowing under snowpacks, although this is stretching it a bit.

Nivation (idea)