Here is a link to a scientific article suggesting a possible mechanism of the Great Flood. For the believers, this does not change what is known as Bible fact. For the scientifically curious, this article may show how the Great Flood is true.
Noah's Flood and the Associated Tremendous Rainfall as a Possible Result of Collision of a Big Asteroid with the Sun
It is interesting that the article finishes with the following statement:
"Humanity even now is not prepared to face such catastrophic disaster so it is important to know its mechanism in order to help to predict it and to make proper actions to reduce the damage cause by it."