On April 28, a fierce hailstorm battered Springfield, Mo., dropping ice chunks the size of baseballs, with some even larger than grapefruits. The giant hail smashed cars, wrecked homes and injured both people and animals.
This type of destructive hail is making headlines more frequently. In a warming world, ice falling from the sky might seem more likely to melt away. But hailstones may instead grow larger and more destructive in many parts of the world, though the risks will vary by region, researchers report May 27 in Nature.
“The study provides an interesting and timely contribution to understanding how climate change may affect hail hazards,” says climatologist Davide Faranda of the French National Center for Scientific Research in Paris. “It combines physical reasoning with climate model projections.”
Hail forms when strong storm winds lift moisture high into cold clouds. There, water droplets freeze around tiny particles and grow until they become too heavy for the winds to hold up. To see how hail may change in a warmer world, researchers at Peking University in Beijing built a computer simulation that estimates how hailstones grow inside clouds based on atmospheric conditions, such as temperature, moisture and wind. The team tested the computer model on more than 14,000 real-world hailstorms around the globe from 2014 to 2021, then used it to explore how those storms might change under future climate conditions.
Large hailstones are expected to become more common, making hailstorms more damaging, the model suggests. That pattern reflects two competing effects. Warmer air can hold more water vapor, giving hailstones more material to grow. At the same time, as the atmosphere warms, hailstones pass through a deeper layer of air warm enough to melt them before they hit the ground.
“Large hailstones melt too, but they can still reach the ground as sizable chunks of ice,” says Qinghong Zhang, a meteorologist at Peking University who led the research. “Smaller hailstones are affected more. They may melt completely and turn into raindrops.”
The danger, the team found, isn’t equal everywhere. Places farther from the equator could get hit harder, while hail damage in tropical and subtropical regions may actually ease. That’s partly because by the end of this century, temperatures are expected to rise more sharply at higher latitudes. The extra warming can strengthen updrafts inside storm clouds, allowing hailstones to grow larger, says meteorologist Shiyi Zhang, also of Peking University.
“This is the first study to make a quantitative estimate of hail hazard events worldwide,” Qinghong Zhang says. The broad conclusion is plausible and fits with earlier work, Faranda says. But he is less certain about the quantitative results and regional forecasts. “Hail is an extremely local phenomenon,” he says. “Global climate models cannot explicitly resolve hailstorms.” That means studies based on broader weather patterns still come with uncertainty.
Qinghong Zhang acknowledges those uncertainties. Still, she says, the team tested its results against hailstorms recorded over the past several decades in China and the United States. Those checks suggest the uncertainties are manageable.
For now, the study offers a clear warning: If temperatures keep rising, larger and more damaging hail will probably become a greater threat in many regions, Shiyi Zhang says.
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