A jökulhlaup (pronounced "yo-KOOL-lahp") is a sudden, massive release of glacial meltwater from a subglacial or proglacial lake, commonly referred to as a glacial lake outburst flood (GLOF)
https://i.redd.it/pnuumpmcb9mh1.jpeg
Source: r/mtg · by /u/SATXS5