Hurricane-proof skyscrapers vulnerable to less powerful windstorms

Tall buildings fare poorly in derechos*, say experts, raising questions over their resilience as climate crisis worsens

Skyscrapers built to withstand major hurricanes fare much more poorly in less powerful windstorms known as derechos, researchers have found, raising questions for cities worldwide over the resilience of tall buildings as the climate emergency worsens.

A team from Florida International University’s (FIU) civil and environmental engineering department studied the unexpectedly severe damage caused to buildings in Houston, a city with 50 skyscrapers of 492ft (150 metres) or more, during the 16 May 2024 derecho.

They found that the storm’s long line of fast-moving thunderstorms spawned “downburst” winds peaking at 90mph that bounced off the buildings and inflicted considerable damage, especially to the facades of structures designed to withstand stronger, category 4 hurricane-force wind speeds of up to 156mph.

The same buildings, by contrast, were virtually unscathed during category 1 Hurricane Beryl in July, when sustained wind speeds were similar to those of the earlier derecho, but without their more erratic, up and down nature, or explosive bursts at or near ground level.

The results were published on Friday by the peer-reviewed science website Frontiers in Built Environment. The FIU study focused on five of Houston’s tallest and most iconic buildings but, the researchers say, it could have profound implications for cities elsewhere as the climate crisis and soaring ocean temperatures fuel stronger and more frequent severe weather events, including hurricanes, fires and floods.

They stress that the wind speeds in a derecho, which can vary from far below major hurricane strength to match or exceed it, is not as consequential as how that wind is dispersed. A “unique characteristic” of a downburst, they say, is how the wind blows outwards in all directions when it reaches the ground.

“When strong winds move through a city, they can bounce due to interference between tall buildings. This increases pressure on walls and windows, making damage more severe than if the buildings were isolated,” said Omar Metwally, an FIU doctoral student and the report’s co-author.

“On top of this, downbursts create intense, localized forces which can exceed typical design values for hurricanes, especially on the lower floors of tall buildings.”

Metwally called it a “one-two punch effect” that the FIU team predicts will become an even worse problem for states around the Gulf of Mexico, where a 0.34F rise per decade over the last half-century is twice the rate of oceans globally.

Amal Elawady, professor of structural and wind engineering at FIU, and the team’s leader, said the research would also have relevance in other countries, where regulations for building design and wind loads are often calculated primarily with hurricane categories in mind.

“It’s not only a US issue. Downbursts are also very common and very frequent in Europe and worldwide,” she said.

“How a building responds to a thunderstorm is different from the way they respond to hurricanes, so it’s something that needs to be considered, not just for the buildings, but also for the components, like the cladding, the envelope of the building.”

Metwally said he hoped the research would lead to a re-evaluation of regulations and design of future tall buildings, as well as urban planning, as officials became more aware of the complexity and potential negative outcomes of downburst events.

The FIU analysis focused on Houston’s Chevron Building Auditorium, CenterPoint Energy Plaza, El Paso Energy Building, RRI Energy Plaza, and Wedge International Tower, all built between 1962 and 2003 and between 518ft and 742ft tall. Construction standards require them to withstand winds up to 67 metres per second, or category 4 hurricane strength.

During last year’s derecho, facade panels were dislodged and cladding damaged, especially on corners and lower floors. Broken glass and other hazardous debris fell on to downtown streets and the aftermath brought significant socio-economic impacts including traffic disruptions, businesses temporarily closing, and a huge bill for clean-up and repairs.

The FIU team ran simulations of the downbursts and hurricanes on modeled replicas at the university’s Wall of Wind experimental facility in Miami, funded by the National Science Foundation. Suction on the sides of buildings was substantially more evident during downburst events, explaining the ripping away of cladding and broken windows that did not occur during the hurricane.

“It’s not likely that a tall building will fail under wind, either hurricane or downburst,” Elawady said.

“But it causes damage, debris and water intrusion, and once you have a broken window you have a change in the internal pressure in the building and then the total force on the building is different,” she said.

Ongoing and future FIU research will look at the effects of downbursts on transmission lines, lighting poles, telecommunication towers and low-rise buildings as well as more studies on skyscrapers.

“It’s a very complex problem that needs to be thoroughly studied, and we’re trying our best to better understand it,” Elawady said.

*A derecho (pronounced similar to "deh-REY-cho") is a widespread, long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms

Source: The Guardian

Climate crisis ‘wreaking havoc’ on Earth’s water cycle

Global heating is supercharging storms, floods and droughts, affecting entire ecosystems and billions of people

The climate crisis is “wreaking havoc” on the planet’s water cycle, with ferocious floods and crippling droughts affecting billions of people, a report has found.

Water is people’s most vital natural resource but global heating is changing the way water moves around the Earth. The analysis of water disasters in 2024, which was the hottest year on record, found they had killed at least 8,700 people, driven 40 million from their homes and caused economic damage of more than $550bn (£445bn).

Rising temperatures, caused by continued burning of fossil fuels, disrupt the water cycle in multiple ways. Warmer air can hold more water vapour, leading to more intense downpours. Warmer seas provide more energy to hurricanes and typhoons,

supercharging their destructive power. Global heating can also increase drought by causing more evaporation from soil, as well as shifting rainfall patterns.

Deadly flash floods hit Nepal and Brazil in 2024, while river flooding caused devastation in central Europe, China and Bangladesh. Super Typhoon Yagi, which struck south-east Asia in September, was intensified by the climate crisis, as was Storm Boris which hit Europe the same month.

Droughts also caused major damage, with crop production in southern Africa halving, causing more than 30 million people to face food shortages. Farmers were also forced to cull livestock as their pastures dried up, and falling output from hydropower dams led to widespread blackouts.

“In 2024, Earth experienced its hottest year on record and water systems across the globe bore the brunt, wreaking havoc on the water cycle,” said the report’s leader, Prof Albert van Dijk.

He said 2024 was a year of extremes but that was not an isolated occurrence. “It is part of a worsening trend of more intense floods, prolonged droughts, and record-breaking extremes.” The report warned of even greater dangers in 2025 as carbon emissions continued to rise .

The 2024 Global Water Monitor Report was produced by an international team of researchers from universities in Australia, Saudi Arabia, China, Germany and elsewhere. The team used data from thousands of ground stations and satellites orbiting the Earth to assess critical water variables such as rainfall, soil moisture, river flows, and flooding.

They found rainfall records are being broken with increasing regularity.

For example, record highs for monthly rainfall were set 27% more often in 2024 than in the year 2000 and daily rainfall records were set 52% more frequently. Record lows were set 38% more often. “So we are seeing worse extremes on both sides,” said Van Dijk.

In southern China from May to July, the Yangtze and Pearl rivers flooded cities and towns, displacing tens of thousands of people and causing hundreds of millions of dollars of damage to crops. The river floods in Bangladesh in August after heavy monsoon rains affected almost 6 million people and destroyed at least a million tonnes of rice.

Meanwhile, in Spain in October more than 500mm of rain fell in eight hours, causing deadly flash floods. The city of Porto Alegre, Brazil, was inundated with two months’ worth of rain in just three days in May, transforming roads into rivers.

“Heavy rainfall events also caused widespread flash flooding in Afghanistan and Pakistan, killing more than 1,000 people,” Van Dijk said. The flooding also displaced 1.5 million people.

In the Amazon, drought struck. “Wildfires driven by the hot and dry weather burned through more than 52,000 sq km in September alone, releasing vast amounts of greenhouse gases,” Van Dijk said. “From historic droughts to catastrophic floods, these extreme events impact lives, livelihoods, and entire ecosystems.”

The researchers said seasonal climate forecasts for 2025 and current conditions suggested droughts could worsen in northern South America, southern Africa, and parts of Asia. Wetter regions such as the Sahel and Europe may face elevated flood risks.

“We need to prepare and adapt to inevitably more severe extreme events,” said Van Dijk. “That can mean stronger flood defences, developing more drought-resilient food production and water supplies, and better early warning systems. Water is our most critical resource, and its extremes – both floods and droughts – are among the greatest threats we face.”

Source: The Guardian

Climate change supercharged late typhoon season in the Philippines

Climate change is making the Philippines more vulnerable to tropical storms, with rising temperatures already putting the country at nearly double the risk of deadly typhoons, scientists said in a report.

The unprecedented formation of four typhoons around the Philippines last month was made 70% more likely as a result of global temperature rises of 1.3 degrees Celsius (2.3 degrees Fahrenheit), researchers with the World Weather Attribution group said in a report.

Though scientists are cautious when it comes to attributing individual weather events to climate change, the consensus is that warmer oceans are intensifying rainfall and wind speeds across the globe.

“Climate change made the conditions that formed and fueled the typhoons nearly twice as likely,” the group said.

Hundreds of thousands of people were evacuated and more than 170 people killed during an unprecedented sequence of six tropical cyclones that landed in the country in October and November, raising concerns that storm activity was being turbocharged by higher sea surface temperatures.

“The storms were more likely to develop more strongly and reach the Philippines at a higher intensity than they otherwise would have,” said Ben Clarke, a weather researcher at Imperial College London, one of the report’s authors.

If temperatures rise to 2.6 Celsius above pre-industrial levels, those same storm conditions would be 40% more likely compared to now, he added.

An analysis published last month by U.S. weather researchers Climate Central said that hurricanes had intensified significantly as a result of record-breaking ocean warming, with wind speeds up by 18 miles per hour (29 kph).

Scientists believe warmer ocean temperatures are intensifying tropical storms by increasing the rate of evaporation. The Intergovernmental Panel on Climate Change said in its latest assessment that there was “high confidence” that global warming would make storms more intense.

It is still unclear whether or not rising temperatures would extend the normal typhoon season or make tropical storms more frequent, but climate activists are concerned.

“We used to have what we called a hazard calendar – now it is just basically the whole year around,” said Afrhill Rances, the Philippines’ representative with the International Federation of Red Cross and Red Crescent Societies.

Scientific report - WNP Typhoons.pdf

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Source: Business World