חֲמֵ֨שׁ עֶשְׂרֵ֤ה אַמָּה֙ מִלְמַ֔עְלָה גָּבְר֖וּ הַמָּ֑יִם וַיְכֻסּ֖וּ הֶהָרִֽים׃
Fifteen cubits upward did the waters prevail; and the mountains were covered.
Targum Jonathan on Genesis
fifteen cubits higher did the waters prevail, and the mountains were covered.