Date of Award

Spring 2023

Document Type

Open Access Thesis



First Advisor

Susan L. Cutter


Flash flooding is the most frequent and damaging type of severe weather globally. In the United States, heat is the only weather-related cause of death more frequent than flooding. However, while the number of deaths associated with other types of severe weather has decreased since the 1950s, the number of flash flood-related deaths has remained steady. Therefore, there exists a need to improve flash flood warning communication.

In this project, it is hypothesized that improving the National Weather Service’s flash flood warning social media graphic by including areas that commonly flood may increase individuals’ perceived storm risk, their intended compliance with the warning message, and intended sharing of the message with others. To test the hypotheses, a new graphic was developed that includes a large map that zooms into the warned area and pinpoints specific intersections and landmarks that are prone to flooding. Additionally, this new graphic removes the population exposure section from the original graphic in lieu of a larger and more zoomed-in inset map. Changes in storm risk perception, intended message compliance, and intended message sharing between the two graphics were collected via a user survey of undergraduate students at the University of South Carolina.

Quantitative survey data indicated that this new graphic does not impact an individual’s perception of storm risk, intended message compliance, or intended message sharing when compared to the original graphic. However, participant comments and investigation into sample subsets revealed that the enhanced graphic may influence some participants’ protective action decision-making compared to decisions they would make after viewing the original graphic.


© 2023, Christopher John Long

Included in

Geography Commons