The devastation of the world-wide flood was horrific. Everything was wiped out. The cities or architectural artifacts were gone. The entire geography of the Earth was altered drastically. If there had been any prevously existing fossils, they would be wiped out. At the beginning of the flood, the water that was under the earth burst forth, which would indicate extreme volcanic activity. Some studies have been done that show that water that had been heated by this volcanic activity would likely have resulted in oceans with water temperatures in the realm of 80 degrees after the flood. Computer models show that oceans at these temperatures would have created the volumes of moisture necessary to produce the glaciers in a very short time and that the observable effect of the glaciers is just what those computer models would predict. The geography that we can observe, the sedimentation, the mountains, the fault lines, are evidence of this great flood. Much of this evidence for the flood is so strong that the flood deniers are forced to make all kinds of illogical and false claims.

More information about the science is available here & here.