Checking a neighborhood's natural hazard risk before you buy

The National Risk Index is FEMA's data on natural hazard risk across the United States. It's meant for emergency planners and for individual residents, and it can help you make choices that protect your home and family.

It rates communities, meaning counties and census tracts, against every other community at the same level. A census tract is a part of a county with about 4,000 people, so a rural county may have only one, and an urban county hundreds or thousands. The ratings describe the area around a house rather than the house itself.

The data is in FEMA's Resilience Analysis and Planning Tool, a free online map. The separate National Risk Index map is no longer available.

What the index measures

Risk in the index combines three parts:

• Expected annual loss. The average economic loss each year from natural hazards, to buildings, people and agriculture, in dollars.
• Social vulnerability. How susceptible the people in the area are to harm from a hazard.
• Community resilience. How well the area can prepare for hazards, adapt, and recover quickly.

Higher expected loss and higher social vulnerability raise the risk score, and higher community resilience lowers it.

The 18 hazards

The index covers avalanche, coastal flooding, cold wave, drought, earthquake, hail, heat wave, hurricane, ice storm, inland flooding, landslide, lightning, strong wind, tornado, tsunami, volcanic activity, wildfire and winter weather. It leaves out man-made hazards, so flooding from a dam failure isn't counted, and it counts only the main hazard event, not what follows from it.

Finding a tract

From FEMA's Resilience Analysis and Planning Tool page, select Access RAPT and agree to the terms. The map opens with a menu across the top. The NRI icon at the far right of that menu lists the National Risk Index layers already loaded, such as the overall risk rating for census tracts. Check a layer's box to show it on the map.

The Legend icon at the far left shows what each color means. Select a county or census tract on the map to see its ratings and scores. For a hazard that isn't preloaded, use Add Data, choose the National Risk Index Dataset and search for the hazard, such as drought.

Reading the scores and ratings

Each area gets an overall score and a score for each hazard. A score is a percentile from 0 to 100 against every other area at the same level. A tract with a score of 84 ranks above about 84 percent of tracts in the country.

Ratings run from very low to very high, in five groups. Some areas instead show:

• Not applicable. The hazard isn't possible there, such as coastal flooding inland.
• Insufficient data. There isn't enough data to work out the loss or the risk.
• No rating. Nothing there is exposed to that hazard, or its calculated frequency is zero.

The limits of a rating

• It ranks the area, not the house. A county can rate high even when most of its tracts rate low, because counties are compared with counties and tracts with tracts.
• A low rating isn't a promise. A hazard that's possible in an area can still happen and cause damage there. The index doesn't predict next year's losses.
• A known hazard can still rate low. An area known for a hazard can score low when its people are less vulnerable or more resilient.
• It doesn't count flood defenses or forecasts. Levees and dams count only where the source data includes them, and the index uses no forecasts or real-time data.
• Local data can be more accurate. The index uses nationwide datasets, which are often less accurate than local data.

An annotated example

What to do next

Open the National Risk Index layers in FEMA's Resilience Analysis and Planning Tool and find the census tract for the house. Note the hazard types rated highest. Then use the Print tool to save a PDF map with the home's records.