When a disaster hits, be it hurricanes, earthquakes or wildfires, knowing how many people live and work in the affected areas is crucial to recovery and rebuilding efforts.

This year’s series of severe natural disasters that destroyed homes and businesses in Florida, Texas and California and caused catastrophic damage in Puerto Rico and the U.S. Virgin Islands has magnified the need for quick and accurate information.

The U.S. Census Bureau’s OnTheMap for Emergency Management is a public data tool that provides a web-based interface to gauge the potential impact of disasters on the workforce and residents of a particular area. Users can gather detailed information on workers, population and housing characteristics for hurricanes, floods, wildfires, winter storms, and federal disaster declaration areas.

OnTheMap for Emergency Management automatically incorporates real-time disaster event boundary updates from the National Weather Service’s National Hurricane Center, Department of Interior, Department of Agriculture and the Federal Emergency Management Agency. These event boundaries are then tabulated against data from American Community Survey (ACS) five-year estimates, 2010 Census, and the LEHD Origin-Destination Employment Statistics (LODES). (LEHD is the Longitudinal Employer-Household Dynamics program at the U.S. Census Bureau.)

An interactive map viewer can display the information in defined geographies at census block, block group, tract, and county-level detail. The ability to pinpoint the count and characteristics of people working and living in affected areas can help in emergency preparedness and recovery efforts. Statistics can even be generated for specific segments of the workforce, including ages, earnings or industry groupings.

In Figure 1 below, ACS population data is being mapped for areas potentially impacted by the Atlas fire that recently roared through parts of northern California (boundary as of October 11, 2017).

Figure 1: Population Characteristics for October 11, 2017 Atlas Fire Perimeter (Source: U.S. Census Bureau, 2011-2015 American Community Survey 5-Year Estimates, accessed via OnTheMap for Emergency Management)

The potential impact of a disaster can also be viewed from a workforce perspective by looking at the demographics and industries of workers employed or living in the area.

“For example, the LODES data set tells us that 23 percent of workers employed in the Atlas fire perimeter work in manufacturing but only 9 percent of workers living in that area are employed in manufacturing,” said Heath Hayward, geographer at the Census Bureau’s Center for Economic Studies.

In Figure 2 below, LODES data for manufacturing employment is being mapped for areas potentially impacted by the Atlas fire (boundary as of October 11, 2017).

Figure 2: Employment by Manufacturing for October 11, 2017 Atlas Fire Perimeter (Source: U.S. Census Bureau, 2014 LEHD Origin-Destination Employment Statistics (LODES), accessed via OnTheMap for Emergency Management)

For a more detailed view of the potential impact of this disaster event, see the Atlas Fire as of Oct. 11, 2017 in OnTheMap for Emergency Management. Also, see the potential impact of the Thomas Fire on Ventura County as of Dec. 7, 2017.

For other examples of disaster events shown in this tool, see the potential impact of imminent flooding in Tippecanoe and White counties in Indiana as of Nov. 21, 2017 and the potential impact of Hurricane Irma as of Sept. 12, 2017.

More information about the LEHD program and OnTheMap for Emergency Management. Please send questions and comments to CES.OnTheMap.Feedback@census.gov.