The southern fire that burns everything at the time of pralaya, also called Vadavamukha. Vadava is the mare, mukha the head, the fire has the shape of a mare’s head. The fire, Agni, is called Vadavagni.
The terrestrial south pole, the north pole is Bhagola.
In the myths the world is burned or flooded, or first burned and then flooded.
Badavamukha and Bhagola are connected with the myth of Aurva.
See also Saptamegha.
Read about the fire here