Destructive winds originating from thunderstorms in the central United States are becoming more prevalent and widespread as global temperatures continue to rise, according to a new study conducted by the U.S. National Science Foundation (NSF) National Center for Atmospheric Research (NCAR). This research, published in Nature Climate Change, highlights a significant five-fold increase in the geographic area affected by damaging straight line winds from thunderstorms over the past four decades. By utilizing a combination of meteorological observations, high-resolution computer modeling, and analyses of fundamental physics, the study sheds light on the alarming impact of these extreme wind events.
Thunderstorms have intensified in recent years, leading to an uptick in extreme wind events. These gusts, reaching speeds of 60 to 80 miles per hour, pose a severe threat to buildings, power grids, and human safety. Straight line winds, caused by powerful downdrafts from thunderstorms, are classified as damaging if they exceed 50 knots or approximately 57 miles per hour. The costs associated with wind damage in the United States amount to an estimated $2.5 billion annually, according to the insurance industry. Furthermore, an exceptionally powerful storm in 2020 known as a derecho caused an estimated $11 billion in damage across the Midwest.
Climate Change and Straight Line Winds
Scientists have long been concerned about the influence of climate change on straight line winds. Previous computer models failed to capture these brief and localized events due to their coarse resolution. Additionally, weather observations have shown a global phenomenon referred to as “global stilling,” where periods of little to no wind appear to become more frequent. Paradoxically, maximum wind speeds can simultaneously increase. In an effort to determine if damaging straight line winds are indeed becoming more extensive, NCAR scientist Andreas Prein turned to a high-resolution computer simulation called CONUS404, collaboratively developed with the U.S. Geological Survey.
By focusing on the central United States, a known hotspot for straight line winds during the summer, Prein used the advanced simulation to obtain a detailed view of wind patterns. Unlike relying on sparse atmospheric observations, the high-resolution modeling enabled the analysis of 109,387 points in the simulation, a significant increase from the previous 95 weather stations. The simulation revealed a startling finding: the area affected by straight line winds has expanded by approximately 4.8 times in the past 40 years. The accuracy of the simulation was further verified by comparing it with historical measurements, including the 2020 derecho, ensuring that these extreme wind events were accurately captured.
The Role of Climate Change in Wind Intensity
Investigating the thermodynamics of straight line winds, Prein explored the impact of climate change on wind events like the 2020 derecho. These winds occur when rain and hail at higher altitudes cool the surrounding air, causing it to descend rapidly and generate intense outward winds at the surface. Prein’s calculations revealed that climate change is amplifying this process by increasing the temperature difference between the cold air in downdrafts and the warm ambient air. As a result, the cold air descends more rapidly, elevating the likelihood of thunderstorms producing damaging winds.
Planning for the Future
The findings of this study emphasize the urgent need to incorporate the escalating risk of straight line winds into climate change resilience planning. Neglecting this perilous phenomenon puts crucial infrastructure at risk. By acknowledging the growing threat of destructive winds, authorities and policymakers can make informed decisions to ensure the future resiliency of communities and infrastructure.
The alarming increase in the geographic area affected by damaging straight line winds from thunderstorms in the central United States demands attention. The integration of meteorological observations, high-resolution computer modeling, and fundamental physical principles has revealed the significant impact of climate change on wind intensity. As global temperatures continue to rise, it is imperative that communities and infrastructure adapt to mitigate the risks associated with these extreme wind events. By incorporating the growing threat of destructive winds into climate change planning, we can safeguard the future resiliency of our society.