Tornadoes are intense and destructive atmospheric phenomena capable of causing catastrophic damage. Understanding their severity requires a standardized system for measuring intensity and destructive potential. The classification of tornadoes is primarily accomplished through the Enhanced Fujita (EF) Scale, which provides a framework for meteorologists and engineers to assess wind speeds based on the damage left behind. This scale helps categorize the violence of an event, ranging from minor tree damage to the complete destruction of well-built structures.
The Most Recent EF5 Tornado
The most recent confirmed tornado to achieve the highest possible rating on the scale was the Enderlin, North Dakota, twister that occurred on June 20, 2025. This powerful storm broke a lengthy period without an EF5 classification in the United States, which had lasted for over a decade. The National Weather Service (NWS) officially determined the tornado’s strength after an extensive damage assessment, upgrading its initial rating to EF5 in October 2025.
The tornado carved a path of destruction over 12 miles long across the southeastern North Dakota prairie. At its peak, the storm grew to a width of approximately 1.05 miles. Estimated wind speeds reached a maximum of 210 miles per hour, well above the threshold for the highest rating. The event resulted in three deaths and caused significant damage to rural infrastructure, including farmsteads and the derailment of several fully-loaded rail cars.
How Tornadoes Are Classified
The intensity of a tornado is officially classified using the Enhanced Fujita (EF) Scale, which became operational in the United States in February 2007, replacing the original Fujita (F) Scale developed in 1971. The update was necessary because the original F-Scale often overestimated the wind speeds needed to cause certain levels of damage. Furthermore, the older system lacked the detailed indicators necessary to account for variations in building construction quality and structural integrity.
The EF Scale addresses these limitations by utilizing 28 distinct Damage Indicators (DIs), which include everything from residential structures and mobile homes to specific types of trees and utility poles. For each indicator, there are up to eight Degrees of Damage (DoD) that correspond to specific physical destruction. Trained NWS personnel survey the damage and compare it to these indicators to estimate the wind speed at the point of damage.
This process results in a rating from EF0 to EF5, based on the estimated 3-second gust wind speed. Tornadoes rated EF0 and EF1 are considered “weak,” with estimated winds between 65 and 110 mph. An EF0 typically causes minor damage, such as peeling off roof shingles or breaking tree branches. EF1 twisters can cause moderate damage, potentially overturning mobile homes or tearing off large sections of a roof.
The next categories, EF2 and EF3, are classified as “strong” tornadoes. An EF2, with winds between 111 and 135 mph, can shift frame houses off their foundations or destroy exterior walls. An EF3, featuring winds up to 165 mph, can cause severe damage, such as tearing the roof and walls off well-built homes or derailing trains.
Why EF5 Tornadoes Are Exceptionally Rare
The EF5 rating classifies a tornado that produces estimated wind speeds of 200 miles per hour or greater. Only a tiny fraction of all tornadoes, less than one percent annually, ever reach the intensity of an EF4 or EF5. The rarity of this classification reflects the extreme atmospheric conditions required and the hyper-specific damage needed for confirmation.
An EF5 tornado produces catastrophic damage. Well-built, substantial homes can be swept completely clean from their foundations, leaving only a bare slab behind. The force is enough to strip the bark off trees and deform large steel-reinforced structures. In the case of the Enderlin tornado, empty rail cars weighing tens of thousands of pounds were hurled hundreds of feet from the tracks, providing quantifiable evidence of the extreme wind speeds.
These rare events require a combination of meteorological factors, typically forming within a powerful, rotating supercell thunderstorm. The atmospheric ingredients must include high amounts of instability, sufficient moisture, and, most importantly, extreme wind shear. Wind shear, which is the change in wind speed and direction with height, creates the horizontal rotation that is then tilted vertically by the storm’s powerful updraft, forming the mesocyclone that spawns the tornado.
The criteria demand near-total destruction of the most robust structures. If a tornado with high wind speeds only passes over open fields or weaker buildings, the necessary damage indicators for an EF5 classification may not be present. Therefore, many devastating tornadoes are ultimately rated as EF3 or EF4, as the evidence of EF5-level damage, such as a foundation swept clean, must be unambiguous and supported by engineering analysis.