Élivágar (The Rivers)

The rivers carry the cold into the gap. In Gylfaginning the Élivágar, glossed Ice Waves, flowed far from their sources until the venom they carried hardened into ice, and layers of frost piled up in Ginnungagap. Vafþrúðnismál says venom drops sprang from them and grew into a giant, and that fire from the south gave the ice life. The entry points out that Gylfaginning never says outright that these are the twelve rivers of Hvergelmir.