Rashi on Genesis 8:14/רש"י על בראשית ח׳:י״ד

1בשבעה ועשרים ON THE TWENTY-SEVENTH [OF THE MONTH] —The rain had begun to fall in the second month on the seventeenth day (Genesis 7:11): the ten days are those by which the solar year exceeds the lunar year; for the punishment of the generation of the Flood lasted a full (i.e. a solar) year (Genesis Rabbah 33:17).

2יבשה WAS [THE EARTH] DRIED — It became hard as is its normal condition.