Rainstorms are getting more intense in many U.S. cities amid human-driven climate change, a new analysis finds.
Why it matters: More intense precipitation events can cause flash-flooding, landslides, dangerous driving conditions and other potentially deadly hazards.
Driving the news: Hourly rainfall intensity increased between 1970 and 2024 in nearly 90% of the 144 locations analyzed, per a new report from Climate Central, a research and communications group.
- Among the cities with an increase, hourly rainfall intensity rose by an average of 15%.
How it works: The researchers divided each location’s total annual rainfall by its total hours of annual rainfall, using NOAA weather station data.
- That approach quantifies how much rain fell for each hour it was raining in a given year — in other words, rainfall intensity.
- Some locations were not included because their stations haven’t consistently collected hourly precipitation data.
Between the lines: Human-driven climate change is resulting in warmer air, which holds more moisture and thus can drive more intense precipitation.
- Hotter temperatures also evaporate more water vapor from lakes, oceans and vegetation.
Zoom in: Wichita, Kansas (+38%), Reno, Nevada (+37%) and Fairbanks, Alaska (+37%) had the biggest gains in hourly rainfall intensity between 1970 and 2024, per the analysis.
- That Reno is in the top three underscores Climate Central’s point that rainfall intensity is rising in places that are generally dry, not just those that get at least a decent amount of annual rainfall.
Threat level: Flooding costs the U.S. economy up to nearly $500 billion annually, by one estimate, and is creating “climate abandonment” zones as people flee for safer areas, Axios’ Andrew Freedman reports.
- Researchers have also found that predominantly Black coastal communities may be particularly vulnerable to increased flood risk over the coming decades, Climate Central notes.
What’s next: The group recommends that people stay aware of their area’s flooding risks, and suggests homeowners carry flood insurance and improve their home’s resiliency against flooding as able.