Colorado experiences frequent tornado activity, sitting at the western edge of the Great Plains, an area known for producing rotating thunderstorms. Because of its unique position, spanning the Rocky Mountains and the high plains, Colorado’s weather patterns are complex. The eastern half of Colorado is considered part of the extended region known as Tornado Alley, alongside core states like Kansas and Oklahoma. The state’s average annual tornado count is high, consistently placing it in the top ten nationally for the raw number of reported events.
Where Colorado Tornadoes Form
The distribution of tornado activity across Colorado is heavily skewed toward the eastern portion of the state, where the terrain is relatively flat and conducive to storm development. Historically, approximately 94 to 95 percent of all documented tornadoes in Colorado have occurred along and east of the Interstate 25 corridor. This region, known as the Eastern Plains, provides the necessary atmospheric instability and moisture for severe weather to form. The western slope and the high mountain counties, located west of the Continental Divide, rarely see tornadoes due to the cold, dry air and disruptive effects of the rugged topography on storm structure.
A significant number of tornadoes occur near the metropolitan areas along the Front Range, primarily due to a localized weather feature called the Denver Convergence Vorticity Zone (DCVZ). The DCVZ forms when moist, low-level southeasterly winds encounter the foothills of the Rockies and the Palmer Divide, a ridge between Denver and Colorado Springs. This collision creates a localized boundary of wind shear and spin, which triggers thunderstorm and tornado formation. Weld and Adams counties, situated near this feature in the northeast, have historically seen the highest number of tornadoes in the state.
Seasonal Patterns and Peak Occurrence
Colorado’s tornado season generally ramps up in the spring and continues through the summer months, with a slightly later start compared to states further south. The tornado threat increases rapidly starting in late April and continues through August, with 90 percent of documented tornadoes occurring during this four-month period. The peak of the season typically occurs between late May and early July. This timing corresponds to when the atmospheric ingredients—warm, moist air from the Gulf of Mexico, cool air aloft, and an initiating mechanism—are most frequently in place over the high plains.
Tornadoes in Colorado are overwhelmingly an afternoon and early evening phenomenon, closely tied to the period of maximum daytime heating. The majority of tornadoes, about 86 percent, are reported between 1:00 p.m. and 8:00 p.m. local time. The most common hour for a tornado to touch down is around 5:00 p.m. While tornadoes have been recorded in nearly every month and hour, those occurring in the early morning or overnight hours are rare events.
Frequency and Typical Intensity
Colorado experiences a high frequency of tornadoes, averaging around 53 annually, placing it among the top ten states for raw numbers. This high count is largely due to the prevalence of landspout tornadoes. Landspouts are typically weaker, non-supercell tornadoes that form from ground-level rotation stretched upward by a rapidly developing cumulus cloud, often along convergence boundaries like the DCVZ. These storms contribute significantly to the high annual total, but they are generally short-lived and less intense than those produced by classic supercell thunderstorms.
The vast majority of Colorado tornadoes are classified at the lower end of the Enhanced Fujita (EF) scale, specifically as EF0 or EF1, meaning they produce minor to moderate damage. Stronger tornadoes, those rated EF2, EF3, or EF4, are far less common. Colorado has never recorded a tornado at the highest intensity level of EF5. This pattern contrasts with the central Plains states, which report fewer total tornadoes but a higher proportion of violent, long-track storms. On average, the state sees an EF3 tornado only about once every three years; these rare, stronger storms are responsible for nearly all tornado-related injuries and fatalities.