After months of cold weather, the month of April is synonymous with light in the northern hemisphere. Rain promotes seed germination, enables flowers to bloom, and replenishes drinking water supplies. However, excessive rainfall can hinder spring planting, cause major floods, and damage infrastructure.
According to researchers, as Earth’s temperatures rise, April showers transform from light drizzles to more intense storms. The U.S. National Climate Assessment states that since the 1950s, significant rainfall events have become more frequent and intense in much of the United States.
As a result, populations are facing more frequent and unprecedented rainfall. For example, in April 2025, torrential rains, flash floods, tornadoes, and hail hit Missouri, Arkansas, Tennessee, Kentucky, and Mississippi, leading to record precipitation in just a few days.
Such a storm is considered rare in the region, but scientists indicate that there is a much higher risk of it occurring today, about 40% higher than centuries ago due to human-induced climate change. The situation is expected to worsen in the coming years.
“In spring, particularly in April, we generally observe more rain, flooding, and rising waters,” explains Jonathan Winter, a climatologist at Dartmouth College.
Today, spring storms are amplified by the warming of the air and oceans. If no weather phenomenon is caused by climate change, the warming creates a water-rich environment conducive to storm development.
“It can be seen as a larger bucket,” explains Jonathan Winter. When an intense storm or cold front arrives, the larger bucket is needed to collect the excess moisture.
Ocean temperature increases can also enhance evaporation, releasing more heat and moisture into the atmosphere. During the record precipitation in April 2025, scientists found that the Gulf of Mexico’s water had warmed by about 1.2°C due to climate change, increasing the moisture available for storms.
However, climate change also affects energy flows entering and leaving the atmosphere, according to Angeline Pendergrass. As water evaporates, it absorbs surface heat and transfers it into the atmosphere. When vapor condenses to form clouds and rain, it releases this energy back to the surface.
Researchers have discovered that these changes in flow accelerate and intensify the water cycle in some regions of the United States and the world.
Extreme precipitation episodes are expected to intensify, especially in spring and in the Midwest. Since 1970, the U.S. has warmed by about 1.4°C, leading to longer heatwaves, more frequent wildfires in the West, and accelerated sea level rise.
The deadly storms that struck the Midwest in April 2025 were relatively rare, even in a warmer world. However, they seem to occur more frequently now, despite the analysis indicating they should happen only about once every ninety to two hundred forty years in the current climate.
“It is quite difficult to predict what will happen… We should not expect everything to evolve in a monotone manner with slight variations from the previous year,” says Angeline Pendergrass. “There is unlikely to be significant flooding, a little more than last year, in the same areas.”
Nevertheless, it is possible to predict which areas are most likely to be affected by floods during an intense rainy episode. According to Jonathan Winter, the most vulnerable places are those at low altitude, already flooded, close to a floodplain, or previously susceptible to flooding.
“We are indeed witnessing episodes of extreme precipitation of unprecedented magnitude,” affirms Jonathan Winter. “However, regarding flood damage, it will occur in places that have already experienced flooding.”
In the northeastern United States, Jonathan Winter is working with agencies such as urban planning and transportation services to better adapt to the evolving extreme precipitation. Some are resizing culverts that channel water, building taller and more resilient bridges, or even proceeding with the proactive evacuation of residents in flood-prone areas.
“We will not be surprised to know who will be most affected by the floods,” says Jonathan Winter.
