Factors that are yet to be explained by those who advocate a worldwide single flood include:
If the flood was global and worldwide there would have been no survivors to relate the event.
If point 1 is somehow explained, all the narratives around the the world of the event would come form the same period - they don't. This implies that local floods were described.
Many cultures such as the ancient Egyptians who were well known for recording events only reported the annual Nile floods and where never annihilated at the supposed time of the global flood.
Throughout history there have been many accounts of floods but none of them global. The melt water from the receding ice caps at the end of ice ages would have created a number of local floods.
