In my book, Storm: Nature and Culture (Reaktion), I discuss a number of ways in which a tropical storm can cause catastrophic damage.
The one usually focused on is the power of the winds, but in addition there is the way sea levels rise because of low air pressure, making flooding more devastating. And then there is heavy rainfall. This has been the biggest problem with Hurricane Harvey, which has been drenching Texas and Louisiana.
During the course of 4 days, some areas suffered more than 40 inches of rain, making Harvey the wettest tropical storm on record to hit the continental United States. At least 47 people have been killed, and 43,000 have had to be housed in temporary shelters. The storm has also been blamed for one death in Guyana.
Brock Long, director of the Federal Emergency Management Agency (FEMA), has described it as the worst disaster in the history of Texas, with damage being estimated at anything up to $190 billion.