Understanding the Rare Storm Threatening the U.S. This Summer
Forecasters warn that a derecho may form over eastern South Dakota on July 28, bringing hurricane-force winds, torrential rain, and flash floods. Derechos are rare but dangerous storm systems capable of causing widespread devastation. Residents are urged to remain vigilant and prepare right away, as previous storms have caused millions of dollars in damage, as per a report by Argus Leader.A rare and dangerous weather event may be unfolding over eastern South Dakota today. On July 28, the National Weather Service is closely monitoring a system that could develop into a derecho, one of nature’s most destructive and least understood windstorms.
Derechos aren’t just thunderstorms. They’re fast-moving, long-lasting walls of violent wind and rain that often leave behind hurricane-scale destruction. And with hot, humid air building across the Plains, conditions are in place once again.
What makes derechos so powerful and rare?
A derecho is a complex storm system, a line of severe thunderstorms that becomes a continuous wave of straight-line winds. These winds often gust over 60 to 100 mph, tearing through buildings, trees, vehicles, and infrastructure. What sets them apart is their scale: derechos can travel hundreds of miles, damaging everything in their path.
“Derechos can go from a calm day to downed trees and roof damage in minutes,” explained Gino Izzi, a meteorologist with the National Weather Service in Chicago. “They’re unpredictable and violent, and they move fast.”
While derechos can occur any time of year, they’re most likely between late July and early August, when hot, moist air mixes with upper-level winds. That’s exactly what forecasters are seeing today over eastern South Dakota.
How has South Dakota been impacted in the past?
This isn’t new territory for South Dakota. The region has seen several damaging derechos in recent years:
- July 13, 2024: A line of storms moved in from Montana, delivering wind gusts of over 100 mph, with one recorded at 108 mph near Hoover.
- July 5, 2022: Skies turned an eerie green over Sioux Falls as gusts near 100 mph knocked out power and damaged homes, fences, and crops.
- May 12, 2022: A massive derecho brought wind, blowing dust, and 34 confirmed tornadoes across South Dakota, Minnesota, and Iowa. One EF-2 tornado ripped through a school in Castlewood.
- These past events have cost millions in damages, closed schools and zoos, and left tens of thousands without electricity, as per a report by Argus Leader.
Could flash flooding make things worse?
Yes, derechos don’t just bring wind. They’re often tied to heavy rain and slow-moving thunderstorms, which can cause flash floods in already-soaked areas. During one derecho in 1969, floodwaters from Ohio’s Killbuck Creek rose over 20 feet, killing two dozen people.
Today’s forecast warns of similar risks. Moisture-heavy air could produce several inches of rain in a short period. If the derecho forms and stalls, localized flooding could compound the dangers, as per a report by the Express News.
Are derechos becoming more frequent?
While derechos remain relatively rare, experts say climate change may be increasing the frequency and severity of extreme weather events like this. “We’re seeing more of these complex, high-energy systems than we used to,” Izzi noted.
Meteorologists urge South Dakotans to take today’s warning seriously. Keep mobile alerts turned on, have a shelter plan ready, and avoid travel until the storm threat has passed.
FAQs
Is a derecho expected to strike South Dakota today?
Yes, the Weather Prediction Center warns that conditions on July 28 may result in a derecho over eastern South Dakota.
What makes derechos so dangerous?
Derechos unleash powerful, straight-line winds, sometimes exceeding 100 mph, that cause widespread damage over hundreds of miles.
