A tornado is a violently rotating column of air extending from a thunderstorm to the ground. While Connecticut is outside the traditional “Tornado Alley,” it experiences a measurable number of these storms each year. These powerful weather phenomena are created by specific atmospheric conditions that allow for the rotation and vertical organization of winds. Understanding the local risk and historical context is important for residents to remain prepared for severe weather events.
The Most Recent Confirmed Tornado Event in Connecticut
The most recent confirmed tornado in Connecticut occurred on September 13, 2023, in Killingly, located in Windham County. The National Weather Service rated this event as an Enhanced Fujita (EF) Scale EF1, indicating moderate wind speeds and damage. The storm moved through the area in the late afternoon, causing a distinct, narrow path of destruction. Damage primarily involved widespread tree failure, with numerous large trees snapped or uprooted, and minor structural damage to roofs.
Historical Frequency and Seasonal Patterns
Connecticut averages around one to three confirmed tornadoes per year, though recent years have sometimes seen a higher frequency. The vast majority of these storms register on the lower end of the intensity scale, typically rated as EF0 or EF1. The seasonal pattern for tornado activity differs from the central United States, peaking during the summer months. The most active time is late spring through summer, with the highest frequency occurring in July and August. This timing correlates with the presence of warm, moist air masses moving northward, which fuel strong thunderstorms capable of producing rotation.
Understanding Tornado Intensity: The Enhanced Fujita Scale
Tornado intensity is measured using the Enhanced Fujita (EF) Scale, which assigns a rating from EF0 to EF5 based on the damage observed after a storm. This scale is an improvement over the original Fujita Scale, using 28 different damage indicators like building types and trees to estimate wind speeds more accurately. The rating is determined by comparing the observed destruction against specific degrees of damage for each indicator.
An EF0 tornado is considered the weakest, causing minor damage such as broken tree branches and loosened roof shingles. Conversely, an EF5 represents catastrophic destruction, where well-built homes are completely swept away. The scale provides wind estimates, not direct measurements, based on the three-second gust needed to produce the observed damage.
Preparedness and Official Confirmation
The National Weather Service (NWS) issues alerts regarding potential and confirmed tornadoes. A Tornado Watch indicates that atmospheric conditions are favorable for tornadoes to develop, signaling the need for residents to be prepared. A Tornado Warning is a far more immediate alert, meaning a tornado has been sighted or indicated by radar, requiring immediate action to seek shelter.
In the event of a warning, seeking refuge on the lowest floor of a sturdy building is the safest action, ideally in an interior room away from windows. After a severe weather event, NWS survey teams examine the path of damage to officially confirm if a tornado occurred. They meticulously compare the damage to the criteria of the Enhanced Fujita Scale to assign the final EF rating.