This claim is often made, but it is very difficult to blame specific weather incidents to larger shifts in climate.
But I have just read a very convincing article from a Weather Channel meteorologist that makes exactly that argument about the recent floods in the American southeast. It is a bit technical, but if you know a little weather science you should be able to follow the argument.
One of the key points to remember about climate is that heat=energy, and the more energy we put into a chaotic system like our climate, the more extreme fluctuations we are going to get. This is similar to how adding a certain amount of energy to a wave tank can cause an even greater increase in wave height than you would expect if the system was linear.
See here for a global view of climate anomalies 2008-2009.
Humans are conducting a huge experiment on the only planet we have, and we are recklessly adding more and more energy to our climate system. Hang on for the ride, it's only going to get bumpier.