Another possibility is detailed in a study entitled Did a Comet Cause the Great Flood? (Carney, 2007), where the researchers gathered not only the account from Noah, but also petroglyphs and oral histories reputed to have drawn and started around the same time as the Noah account in the Bible.
They found massive similarities in what was recorded; from the article:
Almost every culture has a legend about a great flood, and—with a little reading between the lines—many of them mention something like a comet on a collision course with Earth just before the disaster.
The latter being petroglyphs from Native Americans of what appears to be comets, but interpreted by the people at the time as serpents in the sky.
These were alongside finding what appears to be chevrons in southern Madagascar, which are often remnants of past tsunamis.
So the researchers hypothesised that
5,000 years ago, a 3-mile-wide ball of rock and ice swung around the sun and smashed into the ocean off the coast of Madagascar. The ensuing cataclysm sent a series of 600-foot-high tsunamis crashing against the world’s coastlines and injected plumes of superheated water vapor and aerosol particulates into the atmosphere. Within hours, the infusion of heat and moisture blasted its way into jet streams and spawned superhurricanes that pummeled the other side of the planet.
Other evidence that the researchers include is:
Gilgamesh Epic, the hero of Mesopotamia saw a pillar of black smoke on the horizon before the sky went dark for a week. Afterward, a cyclone pummeled the Fertile Crescent and caused a massive flood.
And many oral and petroglyphic histories in South America talk of a great flood.
In India, he notes, a celestial fish described as “bright as a moonbeam,” with a horn on its head, warned of an epic flood that brought on a new age of man.
A Chinese historical record
mentions that the great flood occurred at the end of the reign of
Empress Nu Wa.
Which gives a date for this hypothetical reason as being:
May 10, 2807 B.C.
Then of course, there is the possible physical evidence found by
searching satellite images on Google Earth, she saw dozens of chevrons along shorelines and inland in Africa and Asia. The shape and size of these chevrons suggest that they might have been formed by waves emanating from the impact of a comet slamming into the deep ocean off Madagascar. “The chevrons in Madagascar associated with the crater were filled with melted microfossils from the bottom of the ocean."
Further images and information of the chevrons in Madagascar (and other localities, not necessarily linked to this theory) are imaged and detailed by the Holocene Impact Working Group, where they describe the Madagascan chevrons as being at
the altitude of 205 m above present sea level with in-land penetration up to 45 km.
However, as with many hypotheses, this is not completely proven as the crater itself (if this theory is true) is yet to be identified. But this is presented as another possibility that the Great Flood of Noah's time may have been one part of a global catastrophe.