Climate & Health – National Risk Index
The FEMA National Risk Index provides a holistic view of community-level risk nationwide by combining multiple hazards with socioeconomic and built environment factors. It calculates a baseline relative risk measurement for each United States county and census tract for 18 natural hazard types as a composite score from the summation of all 18 hazard types (as shown in the main table) as well as individual scores for each hazard type (as shown in the breakout tables).
This indicator displays the composite FEMA National Risk Index score and the scores of the three components – Expected Annual Loss, Social Vulnerability, and Community Resilience. All the scores are constrained into a scale ranging from 0 (lowest risk) to 100 (highest risk) describing a community’s relative position among all other communities. For example, a county’s Risk Index score (as shown in the table below) and rating (as displayed in the map inset) is relative to all other counties in the United States. Similarly, a Census tract’s Risk Index score and rating is relative to all other Census tracts in the United States.
Note: Use caution when comparing data for custom areas to national averages. View methodology for more information.
Source
Source Description
The Federal Emergency Management Agency (FEMA) is an agency of the US Department of Homeland Security that is primarily interested in disaster mitigation, preparedness, response, recovery and education.
The National Risk Index (NRI) is a dataset and online tool to help illustrate the U.S. communities most at risk for 18 natural hazards. It was designed and built by FEMA in close collaboration with various stakeholders and partners in academia; local, state and federal government; and private industry. The Risk Index leverages available source data for natural hazard and community risk factors to develop a baseline relative risk measurement for each U.S. county and Census tract. The National Risk Index is intended to help users better understand the natural hazard risk of their communities. For more information, please visit the FEMA’s National Risk Index website.
Methodology
The National Risk Index (NRI) measures the magnitude of risk communities across the US are exposed to in terms of natural hazards. Specifically, 18 types of natural hazards are chosen into evaluation, including 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.
With the 18 natural hazards indicators, the index calculates a baseline relative risk measurement for each United States county and census tract, based on Expected Annual Loss, Social Vulnerability, and Community Resilience. The NRI is calculated using the following formula:
NRI = Expected Annual Loss * Social Vulnerability * ( 1 / Community Resilience)
…where Expected Annual Loss measures the expected loss of building value, population, and/or agricultural value each year due to natural hazards, the Social Vulnerability measures a community’s susceptibility of social groups to the adverse impacts of natural hazards, and Community Resilience uses demographic characteristics to measure a community’s ability to prepare for, adapt to, withstand, and recover from the effects of natural hazards.
An overall composite Risk Index score (for all 18 natural hazards) and individual hazard Risk Index scores (for a single natural hazard) are both calculated for each county and Census tract. Index values range from 0 (the lowest among all other communities for a given component and level-of-detail) to 100 (the highest among all other communities) after being rescaled using min-max normalization. It should be noted that the NRI does not consider the intricate economic and physical interdependencies that exist across geographic regions. The user should be mindful that hazard impacts in surrounding counties or Census tracts can cause indirect losses in a location regardless of the location’s risk profile.
Data was downloaded from the November 2021 release of the National Risk Index. For more information about methodology, please go to the National Risk Index Technical Documentation.
Data Breakouts Available
- National Risk Index Score by Hazard Type
This indicator is available at the following subscription levels:
- Premium (currently viewing this indicator and report combination)