General
There is perhaps no area of the United States that is spared from natural hazards. Coastal areas experience hurricanes and flooding; “tornado alley” spans the central part of the country from the Gulf Coast to North Dakota; earthquake-prone areas are most notably in California, but significant faults also exist in Hawaii, Alaska, South Carolina, and portions of Missouri, Arkansas, and Tennessee; wildfire risk is highest in the West, Southeast, and upper Great Lakes, but structures have been lost across the country due to wildfires; and the frequency of severe thunderstorms and hail is high or very high in at least half of the country!
Although we typically think of durability as “standing-the-test-of-time,” a durable home must also be able to withstand risks in the form of disasters that may last for only minutes or hours. This section of the course therefore provides guidance regarding design and construction methods that will improve a home’s ability to withstand the forces exerted upon it by natural disasters.
Aside from the dialogue about the exact causes of extreme weather events, there is little debate that extreme weather events are becoming more frequent. The Institute for Business and Home Safety, which has tracked the occurrence of disasters and consequent costs to insurance companies since 1950, has shown an increase in the quantity and severity of events over just the past 23 years. Based on industry risk analysis, for example, the number of states experiencing insurance claims valued at over $2 billion rose from only 7 states between 1990 and 1999, to 24 states between 2010 and 2013.29
Local building codes—typically derived from model national codes—establish the minimum level of disaster mitigation that is legally allowed from the standpoint of public safety and general welfare. However, although such measures may be good for the whole, they may not be optimal for any one individual’s circumstances. The building code also maps hazard areas by region when in fact the degree of risk may vary based on site-specific characteristics. For instance, homes located in very open terrain may face greater threat from high winds. Some homeowners may want additional protection from potential damage—especially if the cost of hazard insurance is quite high. Furthermore, it almost always is less expensive to include measures when building a new home rather than go back and try to retrofit later. In short, there are many strong reasons to consider additional, cost-effective disaster mitigation measures for new homes.
The following sections of this chapter outline the major natural hazards and a subset of recommended mitigation measures for each. Note that these measures are only a sample of recommended measures that generally offer a significant improvement for a modest cost. Additional resources for disaster mitigation are then listed at the end of the chapter.
