A destructive tornado outbreak occurred across the Midwest and Ohio Valley on May 15–16, 2025, producing 62 tornadoes and causing dozens of fatalities and billions in damages. The event occurred as a negatively-tilted trough moved into the Upper Midwest. The Storm Prediction Center (SPC) first issued an enhanced risk on May 15 for portions of the Great Lakes and Upper Midwest. Several tornadoes, mostly weak, touched down that day across the states of Wisconsin and Minnesota as embedded storms within a squall line moved through, causing damaging wind gusts.

The most significant tornadic activity would take place in the Ohio Valley the following day. On May 15, the SPC issued a moderate risk of severe weather for portions of Arkansas, Tennessee, Missouri, Illinois, Indiana, Ohio, and Kentucky, effective the following day. Several dozen tornadoes were confirmed on the afternoon and evening of May 16, many of them strong to violent, including a large EF3 tornado that struck the Greater St. Louis area, killing four people, and was the strongest in the area since a violent tornado in 2011. Later that evening, a violent EF4 tornado also prompted the issuance of a tornado emergency for portions of Williamson and Saline counties in Illinois, injuring 7 people. An EF3 tornado in Scott County, Missouri resulted in two fatalities. A strong EF2 tornado in Linton killed one person. A violent, long-tracked EF4 tornado also struck the cities of Somerset and London, Kentucky, killing 18 people and was the deadliest of the outbreak.

There were 26 tornadic deaths, as well as four non-tornadic deaths, associated with this outbreak, primarily from the St. Louis and London tornadoes on May 16, and it was the deadliest in the state of Kentucky since 2021.Wise, A. (2025a, May 17). At least 27 dead after tornadoes sweep through Kentucky and Missouri. NPR. https://www.npr.org/2025/05/17/nx-s1-5402053/tornadoes-kentucky-missouri-deaths Additionally, at least 168 injuries occurred as a result of the outbreak.St. Louis resident describes power of tornado: "Roofs were flying around in the air." (2025, May 17). [Video]. NBC News. https://www.nbcnews.com/weather/tornadoes/st-louis-tornado-storm-rcna207389 With a total of 62 confirmed tornadoes, the outbreak received a score of 57 on the Outbreak Intensity Score (OIS), classifying it as a "major" outbreak. The outbreak caused approximately $5.9 billion (2025 USD) in damages, making it one of the costliest on record.

Meteorological synopsis May 15 Forecast

On the morning of May 15, the Storm Prediction Center (SPC) forecast an enhanced (3/5) risk of severe weather over Minnesota, Wisconsin, Illinois, Michigan, Indiana, and Ohio. A negatively tilted mid-level atmospheric trough was expected to move northeast across the Upper Midwest, which would cause jet streaks to move eastward over the Ozarks and northeastward over the upper Missouri River valley. Large ascent produced by the system was expected to produce a large warm sector throughout much of the Great Lakes and Ohio Valley regions. A surface cyclone was expected to develop over the Dakotas, anchoring a potent warm front that would move north into Wisconsin and a cold front that would move east over the middle and upper Mississippi Valley. Ahead of the cold front would be an area of moderate instability and moist air with dewpoints near , with strong initial wind shear expected to support the development of supercells. Further east, around Milwaukee in southeastern Wisconsin and Chicago in northeastern Illinois, RAP model soundings anticipated moderate MLCAPE values of 2000 J/kg, shear in the lowest of the atmosphere of 35–, and mid-level lapse rates of 7.5 °C/km, in addition to strong storm-relative helicity values of 250–300 m2/s2, which would support severe hazards if mature supercells spread over the area.

The severe weather forecast was predicted to start near the surface cyclone in the upper Mississippi Valley, with individual storms expected to organize into discrete supercells as they exploited the region's conducive deep-layer shear values. This was expected to become a broken line of severe convection, which would move east-northeastward into northern Illinois and eastern Wisconsin as the day progressed. The region was expected to see supercells, some of which might bring strong downburst winds, large hail—up to in the strongest storms—and moderate to strong tornadoes. The broken line was expected to organize into a more linear storm with embedded supercells that might produce tornados and wind gusts exceeding at the leading edge of the line, and hail as the line moved into northern Indiana and Michigan's lower peninsula.

After northern parts of the line moved onto Lake Michigan and as the mesoscale convective system approached landfall onto Michigan's lower peninsula, forecasters noted that shear profiles from Grand Rapids would remain conducive to strong wind gusts and potentially tornadoes, also noting the possibility of embedded mesovortices or rear-inflow jets as inciting factors for either. Throughout the late evening, the system would maintain itself through strong deep-layer shear and higher boundary-level dewpoints, with recorded wind gusts reaching occurring by 9:47 p.m. CDT. Further south over northern Arkansas, existing storms began moving into a destabilized area of the region, though forecasters noted that storms might not intensify because of the presence of substantial convective inhibition in the region.

May 16

The Storm Prediction Center outlined a moderate (4/5) risk over much of the middle Mississippi and lower Ohio Valleys on May 16, with the greatest risk over southeastern Missouri, far northeastern Arkansas, northwestern Tennessee, southern Illinois and Indiana, far southwestern Ohio, and much of Kentucky. The upper-level low centered over the border of North Dakota and Minnesota was expected to move eastward into the middle Mississippi Valley. Following persisting convection from the previous day, a warm front would sweep over a large region from Missouri to the Ohio and Tennessee Valley regions. Over this region, the atmosphere was expected to sharply destabilize, with MLCAPE values exceeding 2500 J/kg, strong mid-level flow, and deep-layer shear that might exceed 50 knots expected to help develop and intensify severe weather.

Severe convection the previous day had persisted into the morning in northeastern Arkansas through eastern Kentucky, which was expected to move east into a destabilizing environment in West Virginia and western Virginia that afternoon, though the longevity of this system was uncertain.

Confirmed tornadoes

Clayton–St. Louis, Missouri/Granite City, Illinois

This extremely large, fast-moving, and deadly tornado caused significant damage to portions of the Greater St. Louis area. The tornado first touched down at 2:39 pm CDT in Clayton just east of I-170 in St. Louis County, Missouri. Upon touching down, the tornado immediately reached EF2 intensity as it moved eastward-southeastward through Clayton, damaging apartment buildings, homes, and low-rise buildings, uprooting trees, and snapping tree branches. Turning east-northeastward, it then caused widespread EF1 damage to trees, power poles, and residences at Fontbonne University; one area of EF2 damage was noted with some power poles that were snapped. The tornado then entered the City of St. Louis, where the tornado sirens failed to sound before the tornado hit as the emergency manager who was supposed to sound them was at training session and away from her office while the back-up button at the fire department was broken and they only received one directive to sound them, but it was garbled and ambiguous.

The tornado continued to produce widespread tree damage as it moved into the city with the St. Louis Zoo also sustaining damage from the storm's rear flank downdraft. The tornado then began to intensify quickly and reached EF2 intensity after crossing Forest Park Parkway. It heavily damaged multiple apartment buildings, damaged homes, shattered windows, and snapped and uprooted numerous trees. In the Central West End and Academy neighborhoods, more homes, churches, mid-rise buildings, traffic lights, power poles, and trees were heavily damaged. Northeast of there, the strengthening tornado blew out the walls and windows and partially and completely removed the roofs of several businesses and brick townhouses, and caused widespread damage to trees, power poles, and traffic lights. Part of the Centennial Christian Church, with three people inside, collapsed with one person later dying from their injuries. Other churches had windows shattered and exterior damage as well. Two areas of low-end EF3 damage occurred on the northwest side of the tornado's path, with a strip mall being partially destroyed and a brick townhouse being flattened; the neighboring brick townhouse was damaged at EF2 intensity.

The now nearly mile-wide tornado then moved through the northwestern part of St. Louis at EF2 intensity. Many brick townhouses and other homes collapsed or were heavily damaged, with roofs removed and exterior walls knocked down; many trees were damaged, and power poles were snapped. The Harlem Tap Room bar, with 20 people inside, also collapsed, but no fatalities occurred there. This damage was also likely caused by the rear flank downdraft as it was outside of the tornado's damage path. The tornado peaked at mid-range EF3 intensity along North Newstand Avenue, flattening multiple brick townhouses. Another brick townhome on Marcus Avenue was also flattened at EF3 intensity, and a church nearby had its roof partially removed and its steeple knocked off. Continuing east-northeastward, the tornado heavily damaged a flagpole as it crossed Route 115 before heavily damaging more brick townhouses, including some that collapsed, other homes, businesses, and churches were heavily damaged and had shattered windows, and power poles and trees were snapped. The tornado then crossed I-70, damaging multiple warehouses and snapping power poles as it moved through an industrial area in a train yard before crossing the Mississippi River into Madison County, Illinois, causing additional EF1 damags to structures before dissipating at 2:53 p.m. CDT.

The tornado was on the ground for 14 minutes, had a path length of , was at its largest width, and moved at an average speed of . The mayor of St. Louis confirmed that five people were killed and the tornado caused $1.6 billion in damage; one of the deaths was later determined to have been caused by wind damage and not the tornado itself, leaving the death toll from the tornado at four. Ameren reported more than 100,000 customers without power in the city. Additionally, 38 people were injured by the tornado.

Shawan–Crowder–Blodgett, Missouri

This narrow but intense tornado touched down over the small community of Shawan in eastern Stoddard County at 3:52 p.m. CDT and moved just south of due east along Route Y. It first caused EF0 damage to the roof of a home, which also had a tree partially fall on it, before snapping trees at EF1 intensity while also inflicting EF0 damage to an outbuilding. The tornado wobbled southeastward and intensified, unroofing a one-story home along County Highway 585 at low-end EF2 strength. Afterwards, the tornado began a more erratic eastward motion as it crossed into Scott County, damaging power poles, flipping irrigation pivots, and snapping and uprooting trees at EF0-EF1 strength. The tornado then struck the community of Crowder, destroying an outbuilding, collapsing part of another, and snapping more trees.