By Jenny Jones


The Federal Emergency Management Agency has released a free online tool to help community planners and other stakeholders visualize natural disaster risk levels in counties and census tracts throughout the United States. The tool could prove useful for engineers, particularly as they guide community-based hazard mitigation planning and/or help clients identify resilient project locations, says Chris D. Poland, P.E., S.E., NAE, F.SEI, M.ASCE, a consulting structural engineer and internationally recognized expert in earthquake engineering and community resource planning.


The National Risk Index provides data for 18 types of natural hazards that could impact communities across the country: avalanche, coastal flooding, cold wave, drought, earthquake, hail, heat wave, hurricane, ice storm, landslide, lightning, riverine flooding, strong wind, tornado, tsunami, volcanic activity, wildfire, and winter weather.


According to the website, FEMA selected these hazards for inclusion in the index based on a review of mitigation plans from all 50 states. The index omits disasters that could occur as the result of human interventions, such as flooding due to a dam failure, or secondary events that could occur following a primary disaster, such as ash and lava spread resulting from volcanic activity.


The index’s interactive map allows users to explore the risk levels for each natural hazard type in specific areas across the country.


This granular perspective is especially beneficial for community planning efforts, such as the prioritization and allocation of resources, emergency operations updates, and risk assessments, according to David Maurstad, the deputy associate administrator for insurance and mitigation for FEMA. “FEMA’s National Risk Index is an invaluable tool that provides communities with standardized risk data for mitigation planning,” Maurstad says. “This data helps policymakers and elected officials prioritize projects that save lives, protect property, and reduce disaster suffering from the devastating effects of natural disasters.”


Available data


In addition to projecting the probability of natural hazards, the index calculates the expected annual loss for each hazard type in areas throughout the country.


According to the website, FEMA used data from state and federal agencies, academia, and other research institutions to develop the EAL, which rates the projected monetary loss of buildings, people, and agriculture from natural disasters.


A community’s EAL is proportional to its hazard risk and relative to other communities. For instance, annual losses from earthquakes are rated from “relatively high” to “very high” throughout coastal California, while annual losses from hurricanes are rated from “very low” to “very high” along the Gulf Coast. The data help “policymakers and elected officials prioritize projects most likely to mitigate disaster costs and suffering,” a FEMA spokesperson said in response to written questions from Civil Engineering.


The index also includes a social vulnerability component that rates how susceptible certain groups are to natural hazard impacts, including disproportionate death, injury, loss, or livelihood disruption. FEMA based its social vulnerability scores on the University of South Carolina’s Hazards and Vulnerability Research Institute’s Social Vulnerability Index, which synthesizes 29 different variables, including vehicle availability, language barriers, family structure, medical disabilities, and health care access, to quantify social vulnerability to natural hazards. “Inequitable planning has put some services out of reach for people based on their race or ethnicity,” a FEMA spokesperson noted.


Poland says the data provide a starting point for communities to consider the extent of how natural disasters could impact their residents. “The inclusion of social vulnerability data in the National Risk Index aligns with the focus that we’ve had during the last year as a nation on equity,” he says. “The more vulnerable a community, the more challenging it will be for them to respond to a natural disaster, and the more help they are going to need. These programs are trying to understand where the vulnerabilities are and where we ought to be spending available mitigation funds to improve the resilience of our local built environment and, at the same time, improve the social structure.”


Poland notes that while the social vulnerability statistics and other data within the index are useful, they are not absolute. According to the website, the index does not explicitly consider things like community changes over time, disaster impacts to infrastructure, critical facilities, transportation, supply chains, and community evacuation efficiencies. Communities should use the index in combination with their own local data for a more holistic understanding of their hazard vulnerabilities, according to Poland. “The index gives communities a common starting point,” he says, “but if the local community has better information, it should use it.”


Engineering applications


According to the website, FEMA plans to regularly update the index as new data become available. Continuously refining and updating the tool is expected to help communities stay informed, which will be particularly important as the frequency and magnitude of natural disasters are expected to intensify as global temperatures rise. “With the increasing threat of climate change, the index informs risk-based decisions, supporting the adoption and enforcement of enhanced building codes and more resilient infrastructure across the nation,” Maurstad says.


The index can also help communities meet mitigation planning requirements. To receive certain types of nonemergency assistance, communities nationwide must submit hazard mitigation plans to FEMA every five years under the Robert T. Stafford Disaster Relief and Emergency Assistance Act. (See FEMA’s fact sheet about using the index for mitigation planning.) Poland says that the index will make it easier for communities and their consulting engineers to develop these plans. “One of the keys to improving our community resilience is for the local professionals in those communities to be knowledgeable and to be able to give good advice,” he explains. “There’s so much information out there (that) it’s hard to do. But the index is a terrific resource that engineers can use to help their communities.”


The index can also help engineers as they consult with clients about where to locate projects, says Poland. Technology companies, for instance, often consider an area’s risk to natural hazard when selecting where to locate their facilities, he says. “If your client is trying to decide where to put their six data centers in the United States to serve their portion of the cloud, this information would be helpful to know,” Poland says. “I encourage my fellow engineers of all disciplines to be grounded in how to think about comparing the risks of various natural disasters. They should have that in mind when working with owners, clients, and communities. The index is a remarkable resource to get them up to speed in a short period of time.”