Genesis 7:11

בחדש השני IN THE SECOND MONTH — Rabbi Eliezer said, “This is the month Marcheshvan”; Rabbi Joshua said, “This is the month Eyar (Rosh Hashanah 11b). נבקעו WERE BROKEN UP — so that they might give forth their waters. תהום רבה THE GREAT DEEP — Measure for measure: they had sinned with רבה רעת האדם “great was the evil of man” (i. e. their sin is described by the word רבה “great”) and they were therefore punished by תהום רבה “the great deep” (i.e. the expression “great’’ is used of the instrument by which they were punished for their great sin) (Sanhedrin 108a).

בִּשְׁנַ֨ת שֵׁשׁ־מֵא֤וֹת שָׁנָה֙ לְחַיֵּי־נֹ֔חַ בַּחֹ֙דֶשׁ֙ הַשֵּׁנִ֔י בְּשִׁבְעָֽה־עָשָׂ֥ר י֖וֹם לַחֹ֑דֶשׁ בַּיּ֣וֹם הַזֶּ֗ה נִבְקְעוּ֙ כׇּֽל־מַעְיְנֹת֙*(בספרי ספרד ואשכנז מַעְיְנוֹת֙) תְּה֣וֹם רַבָּ֔ה וַאֲרֻבֹּ֥ת הַשָּׁמַ֖יִם נִפְתָּֽחוּ׃

In the six hundredth year of Noaĥ’s life, in the second month, the seventeenth day of the month, on that same day were all the fountains of the great deep broken open, and the windows of heaven were opened.