What is responsible for most inland flood fatalities?
By Theresa Barosh | June 2025
Why do about 88 people die from inland flooding every year in the United States? How are they dying?
CIRA researcher Shelby Weder led an effort to delve into flood fatalities. The team said that findings tend to surprise people – the main cause of death is not what most people would guess.
They found that 63% of deaths with known causes were vehicle related through conducting an in-depth review of 2,461 flood-related fatality records from 1996 to 2023.
About ten percent of these vehicle related fatality events included someone driving around barricades or signage to enter the flooded roadway. Even shallow water can move quickly and carry dangerous debris.
Weder also found that 74% of fatalities happen during flash floods versus other types of inland flooding. The team focused on inland flooding because it represents a completely different set of circumstances than coastal flooding, which is often associated with hurricanes. Inland floods can occur because of situations like heavy rainfall, droughts that lead to compacted soil, issues with drainage systems or problems with dams.
While diving into the data, Weder and her team found that looking at national trends could be misleading because there are strong regional patterns. For example, the highest flood fatality month overall for the US is September. However, looking specifically at the Southwestern US, August takes the lead, while July has the most flood related fatalities in the Midwest US. Vehicle-related deaths are much higher than deaths related to being at home, outside, on foot, or recreating in the Midwest, Southwest, and Southeast US. In the Rocky Mountain states, recreation-related deaths during flooding were more comparable to numbers associated with vehicle deaths. Though vehicle-related deaths still took the lead.
Flooding differs by region and season, influenced not only by differences in geography and weather, but also by how people’s circumstances vary across time and place. Weder said, “Looking at fatalities aggregated at the national level misses key regional and seasonal differences and shows the importance of these factors in fatality patterns.”
The Storm Events Database
There is no other dataset like the Storm Events Database in the country. The National Weather Service maintains the Storm Events Database, where Weder accessed fatality information. While flooding related records started in 1996, the database goes back to 1950 for weather events. In 1993 the Government Performance and Results Act was enacted to improve program management in the federal government, with performance measures and reporting. The database is the primary source for official warning verification to assess the reliability of warnings. Additionally, commercial institutions use the records for fatality numbers, while media outlets, the White House, and other federal agencies also cite the database. Beyond the National Weather Service uses, the database is widely used for research, and many other datasets use the records for fatality numbers such as SHELDUS and FEMA’s NRI. SHELDUS is a database of natural and human-made hazards in the U.S. from 1960 to present. The National Risk Index developed by FEMA is a tool designed to assess the risk of natural hazards across U.S. communities.
At the national 2025 American Meteorological Society conference, Weder provided recommendations for maintaining and enhancing the Storm Events Database so that future research can best address how and why people die in weather events.
“We love the Storm Events Database. We just want to make it even better,” said Weder. “It’s important to have better datasets so we can better understand the information – so that we can do good research and find out why people are in these positions. Without the data, it makes that a lot more difficult to find the reasons why people are dying in these weather hazard situations.”
What is needed: Continuation of important records and datasets, along with support for research addressing why and how people make decisions in severe weather situations.