Charles Ellicott Commentary Psalms 29:10

"Jehovah sat [as King] at the Flood; Yea, Jehovah sitteth as King for ever." — Psalms 29:10 (ASV)

The Lord sitteth. —Better, Jehovah was throned upon the flood, and Jehovah will be throned a king forever. The word translated “flood” is, except in this place, applied exclusively to the Deluge (Genesis 6:7). Therefore, we must suppose that the poet was reminded of the great Flood by the torrents of rain then falling. Jehovah sat then upon the waters as their King, and so He will forever be throned on high above the storms of earth. Or, perhaps, the Deluge may have become a proverbial term for any great rain.