Iowa's Surprising 2020 Derecho: What Have Meteorologists Learned?

2026 Spring Liberal Arts and Sciences Dean's Lecture
This lecture will look back at the infamous August 10, 2020, derecho that became the costliest thunderstorm event in United States history, discuss why the weather forecasts of that event were poor, and what research has shown regarding our ability to improve forecasts of extreme derechos like this. Besides its price tag of $12 billion dollars, the August derecho was unique in how intense the winds became and how long they lasted at the locations impacted by the storm. State-of-the-art numerical model simulations will show why the intensity and longevity of the winds were so unusual. Additional model runs that alter the atmosphere to account for the changing climate will be used to provide an idea of how climate change might impact derechos in the future.

William Gallus is a professor of meteorology, having served at Iowa State for 25 years. His research interests include improved understanding and prediction of thunderstorm systems, their evolution, rainfall, and severe weather, as well as prediction of winds for wind energy. He also looks at how climate change might impact extreme weather events.

This lecture recording can be found on the Available Recordings page approximately two business days after the event and will remain accessible for three weeks.