and from the standpoint of key decision makers and organizations concerned with addressing disaster risk and increasing resilience.

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FIGURE 2.1 Floodwaters rise through downtown Cedar Rapids, June 2008, when the Cedar River finally crested at 31.12 feet, more than 19 feet above the flood stage. Source: AP photo/Jeff Robertson.

UNDERSTANDING RISK

Disaster risk comprises four elements: hazard, exposure, vulnerability, and consequence (International Bank for Reconstruction and Development/World Bank, 2010) (Box 2.1). Hazard refers to the likelihood and characteristics of the occurrence of a natural process or phenomenon that can produce damaging impacts (e.g., severe ground shaking, wind speeds, or flood inundation depths) on a community.1 Exposure refers to the community’s assets (people, property, and infrastructure) subject to the hazard’s damaging impacts. Exposure is calculated from data about the value, location, and physical dimensions of an asset; construction type, quality, and age of specific structures; spatial distribution of those occupying the structures; and characteristics of the natural environment such as wetlands, ecosystems, flora, and fauna that could either mitigate effects from or be impacted by the hazard.

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1 The term “community” throughout the report is used very broadly to incorporate the full range of scales of community organization—from the scale of a neighborhood to that of a city, county, state, multistate region, or the entire nation. Where a specific kind of community is intended, the chapter adds the appropriate descriptor.



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