Derechos: The Uninvited Guests in Our Cities
The Unexpected Dangers of Straight-Line Windstorms
A derecho windstorm on May 16, 2024, blew out windows at TotalEnergies Tower in downtown Houston. The sudden and unexpected event raised questions about the vulnerability of "hurricane-proofed" buildings to extreme weather conditions.
The Study: A Closer Look at the Damage
A recent study employed miniature models of skyscrapers to find out why the May 2024 derecho in Houston was able to cause so much damage to "hurricane-proofed" buildings. The study, published in Frontiers in Built Environment, recreated derecho-like conditions in a wind tunnel using scaled models of tall buildings and compared them to hurricane-like conditions. According to the findings, the deadly May windstorm created a unique "bouncing" effect that resulted in more significant damage than its wind speeds would have normally indicated.
The "Bouncing" Effect: A New Concern for Urban Planning and Building Design
The study focused on five Houston skyscrapers: the Chevron Building Auditorium, the CenterPoint Energy Plaza, the El Paso Energy Building, the RRI Energy Plaza, and the Wedge International Tower – all of which were designed to withstand category 4 hurricane winds of up to 67 meters per second. Despite the derecho winds reaching a top speed of 40 meters per second, the bouncing effect caused more damage.
"When strong winds move through a city, they can bounce due to interference between tall buildings," said Omar Metwally, a doctoral student who was the study’s lead author. "This increases pressure on walls and windows, making damage more severe than if the buildings were isolated."
The Impact of Global Warming on Derechos
According to the study’s findings, the Gulf is warming at twice the rate of the global ocean, meaning the straight-line derecho winds are expected to become more common. This poses a significant challenge for urban planners and architects, who must now consider the "bouncing" effect in their designs.
Conclusion
The study highlights the need to re-evaluate construction guidelines for facades to reflect the unique effects of downbursts and thunderstorm winds in derechos. As the world continues to grapple with the impacts of climate change, it is essential to prioritize urban planning and building design that takes into account the growing threat of straight-line windstorms.
FAQs
Q: What is a derecho?
A: A derecho is a type of severe thunderstorm characterized by strong, straight-line winds that can cause significant damage.
Q: How did the study create the "bouncing" effect?
A: The study used scaled models of tall buildings in a wind tunnel to recreate derecho-like conditions and compared them to hurricane-like conditions.
Q: What are the implications of the study’s findings for urban planning and building design?
A: The study highlights the need to consider the "bouncing" effect in future skyscraper designs to protect tall buildings against damage.
Q: How does global warming impact derechos?
A: The Gulf is warming at twice the rate of the global ocean, making straight-line derecho winds more likely to occur in the future.
Q: What is the significance of the study’s findings for the construction industry?
A: The study’s findings suggest that construction guidelines for facades should be re-evaluated to reflect the unique effects of downbursts and thunderstorm winds in derechos.
