While tornadoes are typically associated with spring, winter tornadoes pose a real threat, particularly in Arkansas and the Deep South. The ingredients for severe thunderstorms—strong wind shear, warm temperatures, and humidity—can still come together in winter. The jet stream, which is at its strongest during these months, plays a crucial role, often creating sharp changes in wind speed and direction that fuel storm development.
How Winter Tornadoes Form
For a tornado to develop, there are a few key ingredients that need to align. Wind shear is essential, which refers to the change in wind speed and direction from the ground to the jet stream. In winter, the jet stream can be particularly strong, creating favorable conditions for severe weather. For example, on January 12, 2023, a powerful 125-mph jet stream traversed the Deep South, significantly contributing to tornado formation.
Next, warm, humid air is critical. This is why severe winter storms are rare in the colder Northeast, Midwest, and Northern Plains—it’s simply too cold for the necessary warmth and moisture. However, the Deep South often enjoys warmer temperatures, sometimes reaching into the 60s, 70s, or even low 80s during winter months. Its proximity to the Gulf of Mexico allows warm, moist air to move quickly into the region, providing the instability needed for thunderstorms.
If these conditions exist alongside a strong low-pressure system and an active jet stream, severe thunderstorms—and consequently, tornadoes—can form.
Frequency and Impact of Winter Tornadoes
Winter tornadoes may be less frequent than those in spring, but they still occur. Over the last 20 years, the U.S. has seen an average of 123 tornadoes from December to February each season. However, this average masks significant variability. For example, December 2021 saw a record 232 tornadoes, while other winters might yield only a handful.
These winter tornadoes can be particularly deadly. Since 2005, at least one winter tornado has resulted in fatalities each year. Notably, only three years since 1991—1992, 1994, and 2004—have passed without any deadly winter tornadoes.
Regional Trends
Winter tornadoes primarily affect the Southern U.S., particularly the lower Mississippi Valley, Deep South, and northern Gulf Coast. On rare occasions, tornadoes can extend northward into the Ohio or Mississippi valleys.
The most notable outbreaks in recent history include:
- January 21-22, 1999: A significant outbreak that produced 129 tornadoes, primarily in the South, leading to nine fatalities and 162 injuries.
- February 5-6, 2008: The “Super Tuesday” outbreak generated 86 tornadoes across ten states, including five EF4 tornadoes, resulting in 57 fatalities—the deadliest outbreak since May 1985.
Conclusion
As Arkansas prepares for the potential of winter tornadoes, it’s essential for residents to stay informed and ready. The ingredients for severe weather can come together at any time, and being prepared can save lives. Monitoring local forecasts and having a safety plan in place are crucial steps in staying safe during this unpredictable season.
