Fifteen cubits upward did the waters prevail; and the mountains were covered.
Referenced Verses
Ps 104:6 : 6 Thou coveredst it with the deep as with a vesture; The waters stood above the mountains.
Jer 3:23 : 23 Truly in vain is [the help that is looked for] from the hills, the tumult on the mountains: truly in Jehovah our God is the salvation of Israel.