The El Reno tornado of May 31, 2013, is one of the most significant and studied weather events in modern meteorological history. It developed during a severe weather outbreak across Central Oklahoma. The storm is known for its destructive power, unprecedented physical scale, and highly complex structure, setting a new benchmark for the size of documented tornadic circulations.
Defining the Path and Timeline
The El Reno tornado began its 40-minute duration at 6:03 p.m. Central Daylight Time (CDT) on May 31, 2013. It initially touched down in a rural area approximately 8.3 miles west-southwest of El Reno, Oklahoma. The tornado tracked 16.2 miles across sparsely populated terrain within Canadian County.
The track primarily moved east-southeast before making a sharp turn toward the northeast. This trajectory kept the most intense circulation over open fields, passing south of El Reno and north of Union City. The tornado crossed U.S. Route 81 and Interstate 40 before dissipating around 6:43 p.m. CDT. Although the storm avoided the Oklahoma City metropolitan area, it tragically claimed the lives of eight people who were in vehicles on rural roads and highways.
Record Scale and Intensity
The most defining characteristic of the El Reno event was its sheer physical size, establishing a new record for the widest tornado documented on Earth. At its peak, the tornado reached an unprecedented width of 2.6 miles (4.2 kilometers) across. This measurement was taken as the massive circulation crossed U.S. 81, surpassing the previous record set by a Nebraska tornado in 2004.
The tornado’s destructive power was assessed using the Enhanced Fujita (EF) Scale, which relies on damage indicators to rate intensity. Since the storm tracked mostly over open farmland, there were few permanent structures to indicate maximum wind speeds. Due to this scarcity of damage indicators, the tornado was officially rated as an EF3, corresponding to wind speeds between 136 and 165 mph.
Detailed analysis using high-resolution mobile Doppler radar provided a more complete picture of the storm’s true strength. Radar measurements within the circulation revealed extreme wind speeds exceeding 295 mph (475 km/h) near the ground. These velocities are consistent with low-end EF5 intensity, demonstrating that the tornado was significantly more powerful than its official damage-based rating suggests.
Unique Meteorological Dynamics
The scientific complexity of the El Reno tornado made it exceptionally hazardous and difficult to track. The entire circulation was “rain-wrapped,” meaning it was obscured by heavy precipitation surrounding the vortex. This made visual confirmation of the massive funnel nearly impossible for emergency responders and storm observers.
The tornado was a large, multiple-vortex system, characterized by several smaller, intense circulations known as sub-vortices revolving around the main funnel. These sub-vortices contained the highest wind speeds. The presence and movement of these smaller, rapidly translating vortices greatly increased the tornado’s hazard profile.
The storm also exhibited an unusually erratic track, rapidly changing both its direction and forward speed. At one point, the entire circulation performed a loop before resuming its eastward movement and accelerating to over 50 mph. This rapid evolution and unpredictable motion further complicated attempts to issue accurate, timely warnings for those in the storm’s path.