Major disasters are concentrated geographically. Nearly one-third of all presidentially declared disasters since 1953 have occurred in only 10 states (see Figure 2-2). However, different regions of the country are subject to different types of disasters (see Table 2-1).
Another useful distinction is between hazards, such as tropical storms, that provide advance notice and recur with some regularity, and those, such as earthquakes and terrorist events, that strike without warning (no notice). Communities can plan for the former—the Gulf Coast states are a good example, with their designated evacuation routes and hurricane shelter systems—but planning for the latter is difficult.