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Hailstorms Cause Worse Damage Every Year: Experts

A May 2017 hailstorm in the Denver area caused $2.3 billion in insurance losses. Last week, hail injured 14 people in Colorado Springs and killed at least five animals at the city zoo.

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A girl with a scooter drives through a hailstorm in Munich, Germany
A girl with a scooter drives through a hailstorm in Munich, Germany
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Hailstorms inflict billions of dollars’ worth of damage yearly in North America alone, and the cost will rise as the growing population builds more homes, offices and factories, climate and weather experts said Tuesday.

The role of climate change in hailstorms is harder to assess, the experts said at a conference at the National Center for Atmospheric Research in Boulder, Colorado.

Climate change will most likely make large hailstorms worse, but population growth is more of a certainty, said Andreas Prein, a climate modeling scientist at the atmospheric research center.

“We know pretty certain that we will have more people in the future, and they will have more stuff, and this stuff can be damaged,” Prein said. “I think this component is more certain than what we can say about climate change at the moment.”

This year is expected to be the 11th in a row in which the damage from severe storms exceeds $10 billion in the United States, and 70 percent of that cost comes from hail, said Ian Giammanco, a research meteorologist for the Insurance Institute for Business and Home Safety.

“It’s such a huge driver of the dollar loss each year,” he said.

population growth , climate , hailstorms
Population growth is more of a certainty,than Climate. Wikimedia Commons

Bigger homes, closer together

Costs are rising in the U.S. because homes are getting bigger, from about 1,700 square feet (139 square meters) in the early 1980s to 2,500 square feet (232 square meters) in 2015, he said. New subdivisions also pack homes in more tightly, Giammanco said.

“So it’s a bigger target for hailstorms to hit,” he said.

The effects of climate change on hail and the resulting damage are harder to calculate because hailstorms require distinct ingredients, and global warming affects them in different ways, Prein said.

To form, hailstorms require moisture, an updraft, variable winds and freezing temperatures at lower levels of the storm cloud, he said.

Updrafts lift water droplets into the clouds, where they attract other droplets and freeze together, scientists say. Winds of varying speed and direction keep the droplets suspended in the cloud long enough to grow into hailstones. When they eventually fall, freezing temperatures in the cloud keep them from melting before they hit warmer air closer to the ground.

Climate change will most likely increase updrafts, helping hailstones form, Prein said.

But it will inhibit two hail-producing conditions, he said. Warmer temperatures will expand higher into the atmosphere, so falling hailstones have more time to melt before hitting the ground. And differences in wind speed and direction will subside, he said.

Climate change will make the atmosphere more moist, but the effect that will have on hailstones isn’t clear, he said.

the number of weaker storms but increase the number of severe ones.
The number of weaker storms decrease but increase the number of severe ones. Flickr

More storms that are severe

Kristen Rasmussen, an assistant professor at Colorado State University, said the combined effects of climate change will probably inhibit the number of weaker storms but increase the number of severe ones.

“So we actually think that’s why we’re seeing a decrease in the number of weak to moderate storms and an increase in the most severe storms,” she said. “If those storms are able to break through this inhibition, they … have the potential to be more severe, and they can tap into more energy when they do so.”

The researchers said they need more data to understand the relationship between climate change and hailstorms. Improved science could also help predict hailstorms and calculate risks better, they said.

The Rocky Mountains of Colorado, the Andes in South America and the Himalayas all have conditions that make them hot spots for hail, Rasmussen said.

Also Read: Climate Change Changes The Cost of Eating Veggies

A May 2017 hailstorm in the Denver area caused $2.3 billion in insurance losses. Last week, hail injured 14 people in Colorado Springs and killed at least five animals at the city zoo. Damage estimates were still being compiled.(VOA)

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Skyscrapers May Have Made The Impact Of Hurricane Harvey Worse: Study

The scientists projected future warming and found future versions of the same storms would be significantly wetter and stronger.

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Floodwaters from Tropical Storm Harvey overflow from Buffalo Bayou in downtown Houston, Texas, VOA

Humans helped make recent devastating U.S. hurricanes wetter but in different ways, two new studies find.

Hurricane Harvey snagged on the skyscrapers of Houston, causing it to slow and dump more rain than it normally would, one study found. The city’s massive amounts of paving had an even bigger impact by reducing drainage. Land development in the metro area, on average, increased the chances of extreme flooding by 21 times, study authors said.

A second study looked at last year’s major Hurricanes Maria and Irma and 2005’s deadly Katrina and used computer simulations to see what would have happened if there had been no human-caused global warming. The study found that climate change significantly increased rainfall from those three storms, but did not boost their wind speed.

Both studies are in Wednesday’s journal Nature.

Hurricane, skyscraper
A smoky haze envelopes the skyscrapers and Rocky Mountains that usually can be seen as a backdrop to the city from a high-rise building, Aug. 20, 2018, in Denver. VOA

Houston was a literal drag on Harvey as it sloshed through, with the storm getting tripped up by the skyscrapers, said study co-author Gabriele Villarini, a civil and environmental engineering professor at the University of Iowa.

Co-author Gabe Vecchi, a climate scientist at Princeton University, said that forced the storm to move up higher, causing more concentrated rain over Houston and slowing, which also made more rain.

He compared it to a river running over rocks, creating bubbles.

“That’s sort of what’s going on here,” he said.

This effect is dwarfed, though, by the paving and building that don’t allow water to sink into the ground, Vecchi said.

Harvey’s record rainfall reached 5 feet in one spot near Houston. The scientists used computer simulations to see the effects of urbanization. In parts of the Houston metro area, the effects of development ranged from a 10 percent higher risk of extreme flooding in the less developed northwest to nearly 92 times the risk in the northeast, they reported.

Hurricane Florence, Lawmakers,
A work truck drives on Hwy 24 as the wind from Hurricane Florence blows palm trees in Swansboro N.C. VOA

That’s on top of the unique weather patterns that made Harvey slow down and stall and climate change which brought more water into the storm, Vecchi said.

MIT hurricane and climate expert Kerry Emanuel, who wasn’t part of the study, called the Harvey study “a real advance in our understanding of hurricane impacts on urban areas.”

But Texas state climatologist John Nielsen-Gammon wasn’t convinced. He said the team used generic shapes instead of the actual Houston skyline. He said the storm’s wind speeds may have slowed, but that’s different from the storm’s forward movement slowing.

The other study in Nature looked at a variety of historical damaging storms and tried to calculate past and future effects of climate change. In three cases, the scientists simulated the storms without the changes in the climate from greenhouse gases, showing that global warming increased rainfall 8.9 percent in Hurricane Maria , 6.3 percent in Hurricane Irma and 8.7 percent in Hurricane Katrina .

Maria hit Puerto and Rico and other parts of the Caribbean. Irma hit the Caribbean and Florida, while Katrina struck New Orleans and the Gulf Coast.

Climate Change, Hurricanes
Russ Lewis covers his eyes from a gust of wind and a blast of sand as Hurricane Florence approaches Myrtle Beach, S.C.. VOA

In Maria’s case, a warming climate concentrated heavier rain in the center of the storm and reduced it on the edges, said co-author Michael Wehner, a climate scientist at the Lawrence Berkeley National Laboratory.

For 15 storms, which included the devastating Typhoon Haiyan , the potent Gilbert and 1992’s Hurricane Andrew , the scientists projected future warming and found future versions of the same storms would be significantly wetter and stronger.

Also Read: Vietnam Does Its Part in Cleaning The Environment, Cleans Plastic

“We are beginning to see a climate change influence emerge on tropical cyclones and that’s coming out as rainfall,” said study lead author Christina Patricola, an atmospheric scientist at the national lab.

Although replicating a storm in a different climate is difficult and can’t account for certain changes, this work bolsters science understanding of how climate change alters hurricanes, Emanuel said. (VOA)