Lots of pieces have been written about why Hurricane Irene did so much damage as a Category 1 storm as it skirted the Eastern seaboard. The answer is deceptively simple, but does not fit in with what we have been taught about hurricanes.
Before we examine Irene specifically, let us look at what a hurricane really is. A hurricane is a rather intense form of a tropical cyclone, and we shall use just the term cyclone in general for all of these kinds of storms. There are other kinds of cyclones, but for this piece the unqualified term shall mean tropical cyclones, except at the beginning of the main text where the term cyclone itself is defined.
Before we get started, the only reference that I am going to make to the story of the day is the date in the title. This has been covered ad naseum elsewhere, often with distortions to fit a particular political perspective.