The El Reno tornado, which struck Oklahoma on May 31, 2013, stands as a significant event in the history of severe weather. Its immense scale and unusual characteristics drew considerable attention from meteorologists and the public. This powerful storm carved a path through central Oklahoma, providing valuable insights into the extreme capabilities of atmospheric phenomena.
Defining its Record Size
The El Reno tornado distinguished itself by achieving a record-breaking width, becoming the widest tornado ever recorded. At its peak, this massive twister spanned 2.6 miles (4.2 kilometers) as it crossed U.S. Highway 81 south of El Reno. This dimension significantly surpassed previous records; the average tornado measures about 50 yards (46 meters) wide.
This unprecedented width was primarily determined through high-resolution data collected by mobile Doppler radars, such as the University of Oklahoma’s RaXPol. These specialized radar units, capable of rapid scanning, provided detailed velocity measurements across the tornado’s circulation. The data indicated that the tornado’s immense circulation included areas with high wind speeds extending across its entire breadth. This comprehensive measurement revealed the true scale of the El Reno tornado’s footprint on the landscape.
Unprecedented Wind Strengths
The El Reno tornado also exhibited some of the highest wind speeds ever observed. Mobile weather radars measured extreme winds exceeding 313 mph (504 km/h) within its vortex. These radar-estimated velocities are among the highest documented on Earth, closely approaching the speeds recorded in the 1999 Bridge Creek-Moore tornado.
The tornado’s internal dynamics were complex, characterized by multiple smaller vortices, or “subvortices,” revolving around the main circulation. These subvortices contributed to the overall destructive potential, with some containing radar-indicated winds approaching 200 mph (320 km/h) and moving at ground-relative translational speeds of up to 175 mph (282 km/h). Mobile Doppler units, capable of scanning every few seconds, allowed researchers to capture these intricate and rapidly changing wind fields.
The Meteorological Factors Behind Its Power
The formation and power of the El Reno tornado stemmed from a unique combination of atmospheric conditions. The weather system involved a setup for supercell thunderstorms over central Oklahoma. This environment featured abundant moisture from the Gulf of Mexico, strong instability, and considerable wind shear. Wind shear, the change in wind speed and direction with height, is conducive to the development of rotating thunderstorms, known as supercells.
The El Reno storm was a rain-wrapped, multiple-vortex supercell, its structure obscured by heavy precipitation. This, coupled with its erratic movement, posed significant challenges for tracking and forecasting. A strong low-level jet stream fueled the storm, providing warm, moist air to sustain its growth and intensity. These combined meteorological factors allowed the tornado to evolve into an exceptionally large and powerful system.
Comparing Its Scale
The El Reno tornado holds a unique place in meteorological records, primarily due to its unparalleled width. While its radar-indicated wind speeds were among the highest ever measured, the tornado received an official rating of EF3 on the Enhanced Fujita (EF) scale based on damage surveys. The EF scale rates tornadoes based on the damage they inflict on structures. Since the El Reno tornado remained over mostly rural and sparsely populated terrain, it did not cause the widespread catastrophic damage typically associated with an EF5 rating.
Despite the EF3 damage rating, the scientific community acknowledges the tornado’s extreme intensity, with many considering its true wind speeds consistent with an EF5. If the tornado had passed over a more densely populated area, the damage would likely have been far more severe. Its extraordinary width and powerful internal wind fields, measured by advanced mobile radar, cemented its status as one of the most significant tornadoes ever documented. The El Reno tornado continues to be a subject of intense study, influencing advancements in tornado research and our understanding of severe weather.