Thunderstorm Straight-Line Winds

Severe storms in the U.S. have become significantly more costly, with billion-dollar events increasing more than five-fold between 2005–2024 compared to 1985–2004. While the overall frequency of severe and tornadic thunderstorms has not changed significantly since 1979, tornado activity is concentrating into more frequent and extreme outbreaks, and 'Tornado Alley' has shifted eastward. Projections suggest a 5-20% increase in conditions favorable to severe thunderstorms per 1.8°F of warming, with one study projecting a 6.6% increase in supercell frequency by the end of the century.

• Billion-dollar severe storms in the U.S. have increased dramatically in both frequency and cost. Between 2005 and 2024, there were 168 such events, which is over five times the 30 events recorded from 1985 to 2004. The average annual CPI-adjusted cost rose from $3.8 billion (1985–2004) to $21.8 billion (2005–2024).
• Tornado patterns in the U.S. are shifting despite a stable overall annual count since 1970 (excluding weak events). Activity is concentrating into more frequent and extreme outbreaks, and 'Tornado Alley' has moved eastward since 1979, with more activity in the South, Southeast, and Ohio Valley. Seasonality is also changing, with a decrease in summer activity and an increase in fall activity, particularly in the Southeast.
• Environmental conditions conducive to severe storms are increasing. Since 1979, parts of the eastern U.S. have experienced up to 15 additional days per year with high convective available potential energy (CAPE) during spring and summer. Future estimates suggest a 5-20% increase in favorable conditions for every 1.8°F of warming over the 21st century.
• A 2023 study projects that climate warming will lead to a 6.6% increase in the frequency of supercells nationwide by the end of the century, with a particular increase in the densely-populated eastern U.S.

APA

Climate Central (2025). Thunderstorm Straight-Line Winds. https://www.climatecentral.org/toolkit-severe-weather

Chicago

Climate Central. Thunderstorm Straight-Line Winds. 2025. https://www.climatecentral.org/toolkit-severe-weather.

Wikipedia

{{cite report |author=Climate Central |title=Thunderstorm Straight-Line Winds |date=August 2025 |url=https://www.climatecentral.org/toolkit-severe-weather |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{climatecentral2025thunderstorm, author = {{Climate Central}}, title = {{Thunderstorm Straight-Line Winds}}, institution = {Climate Central}, year = {2025}, month = aug, url = {https://www.climatecentral.org/toolkit-severe-weather}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }