Apart from the storm surge, heavy rainfall causes both flash and long term flooding. Tropical storms and hurricanes are known to dump as much as a meter (about 3 feet) of rain in just a couple of days, creating big problems for residents who believe they are safe just because they do not live on or near the coast. In fact flooding kills more people than the strong winds do. Here are some of the rainfall totals which occurred in October of 1995 from the landfall of Hurricane Opal.
Data provided by TPC
After a hurricane has come inland, it does begin to deteriorate. However, it still produces a lot of rainfall. Even when a tropical system is as weak as a depression, it is still a very strong storm when compared to average thunderstorms.