America’s Tornadoes are Evolving

In the last few weeks a flurry of tornadoes devastated many regions in the midwestern United States.These storm cells left scientists and the communities wondering why tornadoes seem to be increasing in frequency, devastation, and expansion across the United States. Peak tornado season lasts between March and June with approximately 70 percent of yearly storm cells being recorded during those months. However, as a warming climate continues to modify atmospheric conditions scientists are observing certain changes in the aspect of tornado patterns and basic formation. 

The 2023 season has already observed five times reported preliminary tornado reports than the average between 1990 and 2010. The month of January alone had an astounding 168 reports of tornado storm cell activities across the United States. 

While it is still too early to definitively relate climate change to increased tornado activities, scientists are able to correlate some adverse side effects to the subtle evolution of tornado size, span, and frequency as they continue to wreak havoc across the United States each year. 

Understanding Tornado Patterns

Tornadoes are a rapidly rotating column of air that extends from a thunderstorm cell system in the atmosphere to the ground. Tornadoes become visible as they form a condensation tunnel of wind that collects water droplets, dust, and debris. Some tornadoes have been recorded with wind speeds of more than 300 miles per hour, completely destroying anything in their path. These storm cells can be some of the most dangerous and destructive weather phenomena, responsible for countless deaths and economic damages each year. 

Tornadoes occur predominantly in the midwestern United States, but other areas of the world that experience them include Argentina, Bangladesh, and various reports on the other continents. The United States records about 1,200 tornadoes every year, however average reports overtime are somewhat inconsistent because official records only date back to 1950 and recording methods have changed overtime. 

The media often refers to an area of the United States known as tornado alley when discussing these deadly storm cells and their typical range across the United States.Although the region is a relatively common for tornado activities, the idea of “tornado alley” can be somewhat misleading.

Tornadoes have been reported in all fifty states, and many violent tornadoes have occurred outside of “tornado alley”. In the cooler months of the year tornadoes are more likely to affect the southeastern states, while the southern central plains regions are more at risk in the warmer months between May and June, and the northern plains during early summer months. 

Environmental Trends Affecting Tornadoes

To understand how environmental conditions may be affecting tornado storm cell development and resulting damages, meteorologists have been researching trends in their parent strom cell development. The scientists have been closely observing how changes in atmospheric humidity, temperature, and jet stream cycles may affect storm cell formation. 

Most tornadoes in the United States form from an uncommon supercell thunderstorm system which requires moist warm air to form close to the ground and a strong wind shear. The system requires a strong vertical wind shear caused by changing wind speeds and direction closer to the ground to draw the warm moisture up into the atmosphere. The air begins to spin cyclonically as it lifts off of the ground and continues to narrow and increase its cyclonic speed as it begins to form a menacing funnel cloud. The funnel and rotating system are the first indication of a potential tornado, but are only classified as such if they actually touch down on the ground. 

Factors Affecting Tornado Patterns 

• Increased heat and humidity in the atmosphere

• Modifications to the jet stream

• Larger and more frequent supercell thunderstorm systems

Since scientific data is fairly limited and inconsistent, scientists cannot definitively identify long term changes in the storm cells over time. They have described that we are currently in an “experimental” phase studying how tornadoes are evolving, and they can only hypothesize what the future will entail. 

The Future of Tornadoes

As warming surface trends, associated with ongoing climate changes, continue scientists have identified possible modifications to the patterns and formation of tornado storm systems as we have observed over the past 70 years. While long term predictions are not possible due to the lack of consistent and historical data, preliminary conclusions and warnings can be formulated. 

Meteorologists have already recorded an increase in the size and frequency of many supercell tornadoes, as damages have continued to surpass millions of dollars in economic losses each year. Continued expansion of industrial and residential development in at-risk regions has contributed to the increased death toll related to tornadoes in the past decades. Another factor is the increasing spread and range the storms are beginning to acquire, as unprepared regions are exposed to the severe risks associated with tornado development. 

Droughts and atmospheric conditions have resulted in fewer deadly tornadoes in states like Texas, Louisiana, Oklahoma, Kansas, South Dakota, Iowa, and Nebraska. A dangerous tornado developed just last month in New Jersey leaving multiple people dead and more continue to appear in states outside the tornado alley region. The southeastern states have a long wind shear that forms the necessary conditions for tornadoes when combined with increased atmospheric temperature and humidity contributed by climate change. The necessary conditions may suggest the range of tornadoes will continue to expand to bordering states previously at a lower risk to these kinds of natural disasters. Meteorologists also suggest supercell thunderstorm formation will likely shift toward later winter and early spring months rather than summer and fall as seasonality is also affected by climate changes. 

There are many uncertainties associated with how and where tornadoes continue to evolve, but scientists are undoubtedly sure there will be continued increases in devastation, loss of life, and economic damages. The United States population has almost doubled since 1950 and increased development across tornado alley and the east coast, suggesting tornadoes are more likely to affect more people than ever before.