Linking SVRGIS with FEMA Disaster Declarations and Census/ACS

Author/Creator: Amy Read

Specific purpose of code: This code provides examples of how to pull, filter, and merge data from the NOAA/NWS Severe Weather GIS Database (SVRGIS), OpenFEMA Disaster Declarations Summaries, and data from the Decennial Census and American Community Survey (ACS). Walkthroughs are provided for A) merging FEMA disaster declarations to SVRGIS tornado paths data based on incident date and location, B) performing a spatial join between event paths and Census geographies (intersection of line and polygon) to identify geographic areas that were exposed to tornadoes, hail, and/or wind during the user-specified timeframe.

General Application: This template can be extended to access and merge other OpenFEMA datasets based on incident (such as Public Assistance or Individual Assistance summary data), and any other data on Census geographic boundaries that is of interest to the researcher. This code also allows the user to identify FEMA disaster declarations for tornado events at smaller geographic levels (tracts, block groups, etc.).

How does or could this code allow researchers to assess research questions related  to aging or life course?: This code could be used with any of the ACS/Census data subset by age group. Since this code focuses on the spatial join between tornado/wind/hail event paths and Census geographies, any other demographic/health datasets tracked by state, county, tract, block group, etc. could be merged by FIPS code into these data the same way one would combine them with Census data alone.

Data sets used: 

• Population, socioeconomic, or health data: Decennial Census, ACS
• Climate, weather, disaster or environment data: SVRGIS (Tornadoes, Wind, Hail) and FEMA Disaster Declarations Summaries

Are all the data publicly available or are some restricted-access? All are publicly available.  

Links to data:

Coding Language:  R 

Tools and Packages used: tidycensus, rfema, sf, tidyverse

Output(s): Merged dataset saved to .Rds format

Spatial extent: Contiguous United States

Temporal extent: Example focuses on 2000-2010 but explains how to filter/extend beyond that. SVRGIS data is available from 1950 for tornadoes and from 1955 for hail and wind. FEMA disaster declarations are available from 1953. 

Comments: This is a revised, streamlined, and more generalized version of the code used for the manuscript below. That code is also available on the author’s GitHub.

Published papers that use this code: Read, A. (2025). Repeated disaster and the economic valuation of place: Temporal dynamics of tornado effects on housing prices in the United States, 1980–2010. Population and Environment, 47(3), 29. https://doi.org/10.1007/s11111-025-00502-w