IOWA — Sunday marks the five-year anniversary of the Midwest derecho, now known as the most expensive thunderstorm event in modern U.S. history.

Event Overview

• On August 10, 2020, a powerful derecho—a fast-moving, long-lived line of thunderstorms—swept from southeast South Dakota into the Ohio River Valley, carving a 700–770  mile (1,100–1,240 km) path across the Midwest.
• The storm’s duration lasted approximately 14 hours, with sustained damaging winds lasting 30–60 minutes in some locations, far longer than typical derechos.

NEXRAD radar composite as the storm advanced across the upper Midwest.

Wind Speeds & Damage

• Measured gusts reached 126 mph in Atkins, Iowa, with damage estimates up to 140 mph near Cedar Rapids.
• This “land-based hurricane” caused catastrophic destruction: downed trees, collapsed power infrastructure, destroyed buildings, and decimated corn and soybean crops.

During the derecho, wind gusts, some exceeding 120 mph, were strongest along Highway 30 in Iowa.

Human & Economic Impact

• The derecho spawned an outbreak of 26 tornadoes (mostly weak, up to EF1) across several states, including Illinois and Indiana, damaging property but causing no tornado-related casualties.
• An estimated 20%, just over 6 million acres, of Iowa farmland was destroyed due to the winds.
• The storm resulted in 4 confirmed deaths, including a fatality in Iowa. When a bicyclist was struck by a falling tree.
• It is the costliest thunderstorm event in modern U.S. history—estimated damages ranged from $7.5 billion to over $11 billion, depending on the source.

Derecho Climatology shows the average occurrence of derechos, or storms of similar strength in the U.S. Midwest and South.

Localized Impacts

• Cedar Rapids, Iowa, was among the hardest hit: sustained winds and gusts destroyed much of the city’s tree canopy (up to 70%), schools, homes, and businesses. Over 95% of the city lost power, and major roadways were impassable due to debris.
• In Linn County, the storm knocked out power to 91,000 Alliant customers and 31,000 rural meters, some for up to two weeks. An estimated 724,000 acres of forest were lost across Iowa.

Derechos often form along the northern edge of heat domes in the summer; a drought in the summer of 2020 enhanced those conditions.

View images of the storm damage below: