Chronology of the Flood

The story of the flood is recounted in בראשית chapters 6 through 8, and the sequence of events is given in relation to the age of the tale's hero, נח . The flood takes place when נח is 600 years old, which according to the תורה is 1656 years after creation (נח is born in the year 1056). The following chart details the progression of the story. Dates refer to נח 's 601st year- ie, after he's turned 600.

Date Based on נח 's Age (1656 Years After Creation)	Event	Source
Year 480	God tells נח to build an ark and to collect animals.	בראשית ו :יד -כא note #1
Year 600: 10th of the 2nd month	נח fills the ark 7 days before the rains start.	בראשית ז :ד
Year 600: 17th of the 2nd month	The rains begin and fall for 40 days and 40 nights.	בראשית ז :י -יא
Year 600: 27th of the 3rd month	The rains stop. note #2	בראשית ז :יג
Year 600: 17th of the 7th month	Earth remains flooded for 150 days after which the ark comes to rest on the mountains of Ararat and the waters start to recede	בראשית ז :כד , ח :ג -ד
Year 600: 1st of the 10th month	Waters recede until this date, when mountain tops become visible.	בראשית ח :ה
Year 600: 11th of the 11th month	After 40 days נח sends out a raven.	בראשית ח :ו -ז
Year 600: 18th of the 11th month	נח sends out a dove which returns.	בראשית ח :ח -ט note #3
Year 600: 25th of the 11th month	A dove is sent again and returns with a branch.	בראשית ח :י -יא
Year 600: 2nd of the 12th month	A dove is sent a third time and does not return.	בראשית ח :יב
Year 601: 1st of the 1st month	The earth is drying and נח opens up the ark.	בראשית ח :יג
Year 601: 27th of the 2nd month Year 1657 after creation	The earth is dry and the company emerges.	בראשית ח :יד -יט note #4

Note 1. The Torah text does not tell us how long it took נח to build the ark, ie how old he was when he started the project. The midrash (מכלתא בשלח סימן טו ) says it took 120 years. The number 120 comes from בראשית ו :ג - the life of man is ideally 120 years; construction of the ark took 120 years to allow נח 's neighbours time to repent - they were given the full measure of their lives before being destroyed.

Note 2. According to בראשית ז :יא the flood began on the 17th of the second month. בראשית ח :ד says that the ark rested on the mountains of Ararat on the 17th of the 7th month. This is a span of 150 days (see בראשית ז :כד ) which means that, assuming months of equal lengths, this period is five months of 30 days each. This allows us to calculate the date of the end of the rains by adding 13 days from the 2nd month and 27 days from the third (40 = 13 + 27).

Note 3. The תורה does not give us a date for the dove's first mission, but רש "י (commenting on בראשית ח :ח ) explains that because verse 10 says that נח waited another seven days before sending out the dove a second time, we can infer that he had previously also waited seven days after sending the raven. Based on this date, we can infer the next two dates as well.

Note 4. Total duration of the flood: one year and 10 days. Assuming 30 day months - this is 370 days.