With reference to the geomorphological process of Nivation, consider the following statements:

1. Nivation refers to the erosion and weathering of ground beneath and around a persistent snow patch.

2. It mainly occurs due to repeated freeze–thaw cycles and meltwater action.

3. The process results in the formation of a depression known as a nivation hollow.

4. Nivation is primarily a coastal geomorphological process occurring in tropical regions.

How many of the statements given above are correct?