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 well over 200 mph (320 km/h).

The massive multiple-vortex tornado killed eight people, including three storm chasers, and received a damage rating of EF3.

[2][3] In 2019, a brief tornado spawned from an intense squall line struck just southeast of El Reno, killing two people and injuring dozens while again receiving a rating of EF3.

[4] Early on May 24 a strong upper-level trough (an elongated region of low atmospheric pressure aloft) advanced towards the Great Plains out of the southwestern United States and took on a negative tilt, becoming oriented northwest to southeast.

[5][6]: 504 At the same time, southerly flow brought moisture north over Texas and the southern Great Plains, allowing dew points in Central Oklahoma to reach 18–21 °C (64–70 °F).

[6]: 504–505  This moisture, with temperatures in the mid 80 °F (27 °C) range, allowed for ample convective available potential energy (or CAPE, a measure of atmospheric instability); values reached 2500–4000 J/kg.

[7]: 2 [6]: 504–505 In the late morning, a shortwave embedded within the main longwave trough advanced more rapidly, pushing the dryline into western Oklahoma, where it met the already-present moisture.

[7]: 2 This risk was anticipated by the National Weather Service's Storm Prediction Center (SPC), and its local forecast office in Norman, Oklahoma.

The Storm Prediction Center's outlooks for severe weather culminated in a "high risk" area being delineated over the Great Plains for May 24.

"[9] Thunderstorms began to develop before 2:00 p.m. in a north–south oriented line just east of the dryline where the capping inversion was weakest,[6]: 505  including near Altus and Lawton in southwest Oklahoma.

[5] The storm that produced the El Reno–Piedmont EF5 tornado formed approximately 93 miles (150 km) west-southwest of Oklahoma City.

The Lookeba tornado developed at 3:31 p.m. and persisted for approximately 16 minutes, traveling nine miles (14 km) and destroying multiple structures.

[14][2]: 804  After the detection of the wind speeds, the quality of the data degraded until collection ceased altogether at 4:16 p.m., as the tornado progressed to the northeast and towards I-40 where it would produce its most intense damage.

[12]: 4103 When the tornado crossed I-40, the RaXPol radar 6.2 miles (10 km) away was still recording maximum radial velocities over 100 m/s (220 mph), 190 yards (170 m) above the ground.

[16] Their bodies were found more than 300 yards (270 m) north of the interstate, outside their vehicles, stripped of clothing, and rendered "unrecognizable," according to responding state troopers.

Just to the west of the rig, it struck a complex of buildings (including a scrap yard, auto repair shop, garage, and grain storage facility).

"[7]: 7  Flying debris from the salvage yard impacted a new natural gas processing plant operated by Devon Energy, but all employees present avoided injury by sheltering on-site in time.

[27] About three point one miles (5 km) north of Piedmont, the tornado leveled ten homes on Northridge Lane and rolled or lofted vehicles into nearby fields.

A Chevrolet Avalanche parked in the garage of one of the residences was hurled 710 yards (650 m) to the northeast and into a thicket of trees in a ravine, which were debarked and relieved of their branches.

[13]: 2–3  In the subdivision of Falcon Lake, five miles (eight km) northeast of Piedmont and on the border of Canadian and Kingfisher counties, multiple homes again had the walls removed from their concrete slab foundations.

[16] Following the tornado, first responders in Canadian County scoured the 10–20-square-mile (26–52 km2) debris path in the corridor west of El Reno near the interstate.

[19] In an overview of the outbreak in a paper presented at the annual American Meteorological Society conference, National Weather Service authors speculated that the relatively low number of fatalities during the outbreak (which involved three violent tornadoes near a major metropolitan area) was due in part due to "the incredible reaction of the community to not only watches and warnings, but also to the forecast of severe weather" on May 24.

[7]: 2 The Devon Energy natural gas plant near El Reno was forced offline for several weeks as the company assessed and repaired the $140 million facility.

[5] The only government assessment of damages appears in the tornado's entry in NOAA's NCEI Storm Events Database, which predicted that the total was "probably going to be well in the tens of millions.