DOI: 10.17603/ds2-t58y-2s28
title:  StEER: 2025 May 16 St. Louis Tornado Joint Preliminary Virtual Reconnaissance Report-Early Access Reconnaissance Report (PVRR-EARR)
title: in StEER - 2025 May 16 St. Louis Tornado 

description: The primary product of StEER’s Level 2 to the 2025 St. Louis Tornado is this Joint Preliminary Virtual Reconnaissance Report-Early Access Reconnaissance Report (PVRR-EARR), which is intended to: (1) Provide an overview of the 2025 St. Louis Tornado, particularly relating to tornado impacts to the built environment, (2) Provide an overview of the regulatory environment and construction practices in the affected area, (3) Introduce the data collection methodology and chronology, (4) Summarize key observations from the field; and, (5) Provide recommendations for continued study of this event by StEER and the wider engineering reconnaissance community. Note that all observations and findings provided in this EARR should be considered preliminary and are based on the limited scope of the locally-led FAST.
description: A regional tornado outbreak struck the central United States May 15-16, 2025 with a total of 60 confirmed tornadoes that claimed 27 lives and injured at least 168 others in Missouri and Kentucky. Among these tornadoes was a large, fast-moving, and deadly EF-3 tornado that tore through the urban areas of Greater St. Louis, Missouri on the afternoon of May 16, 2025, from approximately 2:41 PM to 3:06 PM. It then crossed the Mississippi River and entered Illinois near Venice, tracking through Granite City before dissipating near Edwardsville. With a damage path 23.3 miles long and one mile at its largest width, the tornado impacted about 16,000 residential, commercial, and industrial buildings, and damaged many electricity distribution poles and lines, causing more than 200,000 customers to lose power. In St. Louis, about 5,000 buildings were damaged, resulting in an estimated $1.6 billion of property loss, 38 injuries and five fatalities, four of which occurred due to the collapse of buildings, making it the largest weather disaster in the state of Missouri since the 2011 Joplin Tornado. 

Given the proximity of members in the vicinity, StEER supported local Field Assessment Structural Teams (FASTs) in their self-directed surveys of the St. Louis tornado in two phases on May 22 and May 25-28, 2025. The first phase was conducted by a FAST with faculty and students from Auburn University, the University of Illinois at Urbana-Champaign, the Ohio State University, and Texas Tech University who deployed for a few hours following the 15th Americas Conference on Wind Engineering held in neighboring St. Charles. The second phase was led by a FAST from the Missouri University of Science and Technology. Due to the large number of buildings that were damaged, the second phase used unmanned aerial surveys to swiftly collect footage along the damage path; the footage was then reviewed and records were created in StEER’s Fulcrum app reporting the global damage rating for each building along the tornado path.   

In general, the FAST observed: 1) a wide damage path with a relatively indistinctive damage gradient within the damage extents; 2) primarily roof damage with intermittent wall collapses in both commercial and residential structures; 3) total collapse of multiple unreinforced masonry buildings; 4) variations in damage based upon the shape of the roof (sloped roofs seemed to perform better than flat roofs) and the local fetch/exposure of structures (more damage to buildings with larger open areas around them); and 5) damage propagating to other parts of the roof due to collapsed parapets and chimneys.

This project encompasses the products of StEER's Level 2 response to this event: a Joint Preliminary Virtual Reconnaissance Report-Early Access Reconnaissance Report (PVRR-EARR) with corresponding Media Repository.