Assessing Hazards

There are a growing number of tools and approaches for addressing the risk and vulnerability associated with coastal hazards from storms. A risk and vulnerability assessment helps to identify people, property and resources that are at risk from injury, damage or loss from hazardous incidents or natural hazards. This information is important to help determine and prioritize the precautionary measures that can make a community more disaster-resistant.

Risk and Vulnerability

Risk areas identify those areas that are most likely to be affected by a given hazard. People and resources located within the risk areas are considered to be at risk from hazards and may or may not be vulnerable to hazard impacts.

The vulnerability of the people and resources within the risk areas is a function of the community’s susceptibility to the hazard impacts.

Toolkit Case Study: Identification of Hazards

The cases in this toolkit are focused on hazards analysis identifying the risk and vulnerability of coastal communities in the panhandle of Florida. The first step toward narrowing the focus of a risk and vulnerability assessment involves determining which hazards to evaluate, as well as the areas potentially affected by those hazards. GIS data for risk and community vulnerability is from the National Oceanic and Atmospheric Administration NOAA Coastal Risk Atlas.

  • Risk — Coastal areas most susceptible to risk of hazards from storm surge (category 3 hurricane) and flooding (100 year floodplain) were identified first. The areas at risk from storm surge were mapped using output from the NOAA Hurricane Storm Surge Inundation Model, known as Sea, Lake and Overland Surges from Hurricanes (SLOSH). Other risk factors not analyzed here include erosion and wind.
  • Community Vulnerability — Communities were then assessed for vulnerability. The focus of these cases was on demographic variables indicating communities that might be most vulnerable to coastal hazards because of societal factors such as poverty and poor infrastructure that would limit their response ahead of and after storm hazards. The demographic variables included:
    • Poverty
    • Low education
    • Language barrier
    • Lack of transportation
    • Elderly
    • Single parent households
    • Mobile homes
    • Rental housing
    • Pre-1970 structures
    • On public assistance

U.S. Commission on Ocean Policy Recommendations Regarding Natural Hazards

  • Enhance technical assistance for developing and improving hazard mitigation plans.
  • Improve the collection and use of hazards-related data.
  • Update the National Flood Insurance Program (NFIP) to reflect beneficial land use in high-hazard areas.

NOAA Coastal Services Center (CSC)

NOAA CSC has been a leader in developing tools and approaches for identifying the risk and vulnerability of coastal hazards. Their websites contain in depth treatments of the issues, tools and approaches that are highlighted here.

Hurricane Ivan, September 2004, less than 24 hours from landfall in the Florida Panhandle. Image courtesy NOAA.

Hurricane Ivan, September 2004, less than 24 hours from landfall in the Florida Panhandle. Image courtesy NOAA.

These variables were assessed based on census block group boundaries with data from the U.S. Census Bureau. Only the most vulnerable communities on the coast were considered.

There are many other types of factors that could be considered in a vulnerability analysis including factors associated with the locations of critical facilities (hospitals and fire stations) or other economic factors such as the location of key businesses that provide taxes and jobs or facilities with potentially harmful chemicals.