2011 El Reno–Piedmont tornado

During the evening hours of May 24, 2011, a large, long-tracked and exceptionally intense EF5 tornado, commonly known as the El Reno–Piedmont tornado or the El Reno EF5, impacted areas near or within the communities of El Reno, Piedmont, and Guthrie, killing nine people and injuring 181 others. After producing incredible damage in several locations along a path of more than 60 miles (97 km), the tornado was given a rating of EF5 on the Enhanced Fujita scale, with peak wind speeds in excess of 210 mph (340 km/h), although a mobile Doppler radar found that the tornado possessed wind speeds of up to 295 mph (475 km/h). The tornado was the first F5/EF5 tornado to occur in Oklahoma since May 3, 1999, when an F5 tornado devastated areas in and around the Oklahoma City metropolitan area.

The tornado touched down in southwestern Canadian County and quickly became violent, debarking numerous trees as it passed through areas several miles southwest of Calumet. As it approached and crossed I-40 west of El Reno, it reached its maximum intensity. A nearby 20,000-pound (9,100 kg) oil tanker truck that was parked at an oil production site near the interstate was thrown approximately one mile (1.6 km) into a wooded gully. Several homes were swept completely away along I-40, trees were completely debarked, and the ground was heavily scoured in some areas. At the nearby Cactus-117 oil rig site, a 1,900,000-pound (860,000 kg) oil derrick was blown over and rolled three times. The tornado weakened slightly as it passed north of El Reno and continued northeast, producing EF3 to EF4 damage in rural areas. The tornado then re-intensified and passed northwest of Piedmont at high-end EF4 intensity, leveling multiple homes and causing additional fatalities. Moving into Kingfisher County and Logan County south of Cashion, the tornado fluctuated several times between EF2 and EF3 intensity causing varying degrees of damage. Afterwards, the tornado then rapidly weakened, causing EF0 to EF1 damage along the north side of Guthrie before dissipating.

2011 was a prolific year for tornadoes and tornado-associated fatalities, with multiple destructive outbreaks. The El Reno–Piedmont tornado occurred during an outbreak across Oklahoma and the Great Plains that produced multiple strong to violent tornadoes near the Oklahoma City metropolitan area on May 24, and was itself part of a tornado outbreak sequence spanning from May 21–26. The Oklahoma storms came just two days after a devastating EF5 tornado struck Joplin, Missouri, which killed 158 people and became the costliest tornado in U.S. history. Additionally, the city of El Reno has infamously been the site of other intense tornadoes. On May 31, 2013, a tornado just south of the town became the largest ever recorded, with a width of 2.6 miles (4.2 km) and radar-indicated wind speeds in excess of 296 mph (476 km/h). The massive multiple-vortex tornado killed eight people, including three storm chasers, and received a damage rating of EF3. In 2019, a brief low-end EF3 tornado that spawned from an intense squall line struck just southeast of El Reno, killing two people and injuring dozens of others.