What is the physical evidence for a global flood? Young Earth Creationists believe in a young earth, followed by a literal global flood based on the belief that Scripture is written as history.  Often, in comments, discussion forums, and discussions in general, they will refer to "overwhelming physical evidence" that backs up their theological belief.

What phsyical evidence do they teach or believe can be interpreted as consistent with the idea of a global flood?
The Answers in Genesis website has an article that covers historical records of the flood - 
Comparison of secular historical records, where they look at 200 flood traditions from across the world.  95% of the traditions had common elements with the Genesis account and described a worldwide flood. 

Answers in Genesis also provides a number of articles describing geological evidence for a worldwide flood: Geological Links