FEMA National Risk Index

Addresscloud offers comprehensive coverage of key perils for the US, sourced from trusted, high-quality data providers with a proven track record in the insurance industry. This section focuses on perils scores provided under the National Risk Index (NRI) from FEMA. The scores and values presented by Addresscloud are as provided by FEMA, without any derivations or modeling from Addresscloud.

1. What is it?

The National Risk Index (NRI), developed by FEMA, is designed to visualize the risk profiles of U.S. communities concerning 18 natural hazards. It provides a relative risk measurement for counties and census tracts across all 50 states, the District of Columbia, and five U.S. territories. The NRI supports planners, emergency managers, and decision-makers in emergency operations planning, resource allocation, risk communication, and community resilience efforts.

The initiative for the National Risk Index began in 2016, aiming to establish a comprehensive, multi-hazard risk assessment. The index considers the likelihood and consequences of natural hazards along with social vulnerability and community resilience. The development process involved extensive collaboration with federal, state, and local governments, academic institutions, non-profit organisations, and private industry. Workshops and working groups were formed to define the methodologies and translate raw data into meaningful risk factors.

Note: The address-level information provided by Addresscloud is derived from the census tract in which the address is located. Perils scores will be the same for all addresses within the same census tract. Census tracts are small, relatively permanent geographic entities within counties, generally housing between 2,500 and 8,000 residents, with boundaries following visible features.

2. How can I use it?

The NRI is a versatile tool for various applications:

• Hazard Mitigation Planning: Identifying and prioritizing mitigation strategies to reduce risk.
• Emergency Management: Enhancing preparedness and response plans based on community-specific risk profiles.
• Community Resilience Building: Informing initiatives to strengthen the ability to withstand and recover from hazard events.
• Public Awareness Campaigns: Educating residents about local hazard risks and promoting proactive measures.

3. How is the data created?

Initiated in 2016, the NRI aims to establish a comprehensive, multi-hazard risk assessment by considering the likelihood and consequences of natural hazards, along with social vulnerability and community resilience. Its development involved collaboration with federal, state, and local governments, academic institutions, non-profit organizations, and private industry. Workshops and working groups defined methodologies and translated raw data into meaningful risk factors.

The selection of the 18 natural hazards was based on a review of FEMA-approved State Hazard Mitigation Plans from all 50 states. Hazards were included if identified in at least half of the state plans or deemed regionally significant. Key U.S. agencies supported the development of the NRI, providing data and expertise for various hazards.

Natural Hazard Selection

The selection of the 18 natural hazards was based on a review of FEMA-approved State Hazard Mitigation Plans from all 50 states. These hazards include avalanches, coastal flooding, cold waves, droughts, earthquakes, hail, heat waves, hurricanes, ice storms, landslides, lightning, riverine flooding, strong winds, tornadoes, tsunamis, volcanic activity, wildfires, and winter weather. Hazards were included if they were identified in at least half of the state plans or deemed regionally significant. 

A range of key US agencies have supported the development of the NRI,  for example:

• Avalanche: Data from the National Avalanche Center and historical occurrence records are used to assess the risk of avalanches in susceptible counties.
• Coastal Flooding: The analysis includes high tide flooding and floodplain data from NOAA and FEMA’s Flood Insurance Rate Maps.
• Earthquake: Earthquake risk is evaluated using data from the USGS and FEMA’s Hazus model, which estimates potential losses based on seismic activity.
• Hurricane:The risk assessment for hurricanes incorporates data from NOAA’s National Hurricane Center and historical storm tracks.

4. Are there any limitations?

While the NRI offers a comprehensive view of natural hazard risks, users should be aware of certain limitations:

• Data Currency: The index relies on the most recent data available, which may still have inherent time lags.
• Resolution: Risk assessments are provided at the census tract level, which may not capture localized variations in risk.
• Assumptions: The methodology assumes that past hazard occurrences and impacts are indicative of future risks, which may not always hold true due to changing climate conditions and other factors.

5. What data points are available?

The NRI includes data on the following natural hazards:

• Avalanche
• Coastal Flooding
• Cold Wave
• Drought
• Earthquake
• Hail
• Heat Wave
• Hurricane
• Ice Storm
• Landslide
• Lightning
• Riverine Flooding
• Strong Wind
• Tornado
• Tsunami
• Volcanic Activity
• Wildfire
• Winter Weather

For each hazard, the NRI provides metrics such as Expected Annual Loss (EAL), social vulnerability, and community resilience indicators.

Risk Analysis Overview

The risk analysis methodology integrates three primary components: natural hazard risk, social vulnerability, and community resilience. The index calculates Expected Annual Loss (EAL) for each hazard, which involves estimating the frequency and consequences of hazard events. This approach provides a standardised measure to compare risk levels across different communities.

In the National Risk Index, natural hazards are represented in terms of Expected Annual Loss, which incorporate data for exposure, annualised frequency, and historic loss ratio.

Social Vulnerability and Community Resilience

Social vulnerability assesses the susceptibility of social groups to harm from natural hazards. This component considers factors such as income, age, disability, and housing conditions. Community resilience evaluates the ability of a community to prepare for, respond to, and recover from hazard events. Data sources for these components include the CDC’s Social Vulnerability Index and Baseline Resilience Indicators for Communities.

Data and Methodologies

Data used in the National Risk Index are sourced from various federal and state agencies, research institutions, and existing databases. The methodology for each hazard type includes detailed steps for data collection, processing, and analysis. For example, the calculation of EAL involves determining the annualised frequency of hazard events and their potential impacts on buildings, population, and agriculture.

Expected Annual Loss (EAL) Calculation

The EAL calculation is a core part of the risk assessment. It combines the annual frequency of hazard events with the expected consequences in terms of economic loss, fatalities, and other impacts. The methodology accounts for both direct and indirect losses and uses historical data to validate the estimates.

6. Where can I find out more?

For more detailed information, you can visit FEMA's official National Risk Index website, or consult the NRI's comprehensive technical documentation.

Note: This document is based on information available as of February 4, 2025. For the most current details, please refer to the official Addresscloud resources