The 2020 Midwest Derecho
Community SafetyBy Director of Research and Development Randall H. Miller
2020 was a year of calamities, rightfully headlined by COVID-19. However, it also included hurricanes, earthquakes, civil unrest and the costliest derecho on record. A derecho is a complex of thunderstorms with winds greater than 58 mph (95 kph) with windspeeds over 100 mph (160 kph) common and travels more than 240 miles (385 km), although distances of over 700 miles (1,125 km) not unusual. Derecho winds are straight line, although they can generate tornadoes (Miller & Kempter, 2018).
The 2020 midwestern derecho began near the state lines of Nebraska, South Dakota and Iowa on August 10. Over the next 14 hours, it traveled nearly 775 miles (1,245 km) to Indiana at an average speed of 55 mph (90 kph) (Anonymous, 2021). The National Weather Service determined that damage was consistent with intermittent straight line winds between 100 and 130 mph (160 and 209 kph) and concluded that maximum wind gusts exceeded 140 mph (225 kph), although the highest measured gust was 120 mph (193 kph).
Damage was exacerbated by high winds that lasted between 30 and 60 minutes, which is an unusually long period for a derecho (NOAA, 2020). The National Weather Service confirmed 20 tornadoes associated with the storm (NOAA, 2020b). Over 8,200 homes were destroyed in Iowa alone (State of Iowa, 2020), and Cedar Rapids, Iowa, lost half of its tree canopy (Jordan, 2020). The total damage across the affected region exceeded $11.2 billion, making it the costliest thunderstorm in U.S. history (NOAA, 2021).
Utilities in Iowa, Wisconsin, Illinois and Indiana were affected, with over 1.4 million customers left without power. That included more than 770,000 ComEd customers, 200,000 Alliant Energy customers and 290,000 MidAmerican customers, among other utilities. Many responding utility employees were without power or had their own property damaged by the storm. Response for some utilities was compromised by crews providing mutual assistance in the Northeastern U.S. in response to Hurricane Isaias. Those crews had to return to the Midwest for derecho recovery. In addition, utilities received mutual aid from entities throughout the region. For example, MidAmerican Energy received assistance from 24 states, some from as far away as Oregon (Ewers, 2021). Many customers were without power for weeks.
Recovery from the tree canopy loss is still underway. The Wright Foundation for Sustainability and Innovation is awarding up to $100,000 in grants for tree canopy improvement in the Midwest, including to replant for derecho recovery. It was one of many initiatives in response to the storm.
Works Cited
Anonymous. (2021, May 13). August 2020 Midwest Derecho. Retrieved from Wikipedia: https://en.wikipedia.org/wiki/August_2020_Midwest_derecho
Ewers, J. (2021, May 12). Director of Operations Support. MidAmerican Derecho August 2020. Des Moines, IA, USA: MidAmerican Energy Company.
Jordan, E. (2020, August 15). Cedar Rapids loses half its tree canopy in derecho. The Gazette.
Miller, R., & Kempter, G. (2018). Utility Arboriculture: The Utility Specialist Certification Study Guide. Champaign, IL: International Society of Arboriculture.
NOAA. (2020, October 8). Midwest Derecho – August 10, 2020. Retrieved from National Weather Service: https://www.weather.gov/dvn/summary_081020
NOAA. (2020b, August 10). August 10, 2020: Derecho Brings Widespread Severe Wind Damage Along with Several Tornadoes. Retrieved from Natonal Weather Service: https://www.weather.gov/lot/2020aug10
NOAA. (2021, May 13). Billion-Dollar Weather and Climate Disasters: Events. Retrieved from NOAA National Centers for Environmental Information: https://www.ncdc.noaa.gov/billions/events/
State of Iowa. (2020, August 16). Governor Reynolds formally requests expedited Presidential Major Disaster Declaration. Retrieved from Office of the Governor of Iowa: https://governor.iowa.gov/press-release/governor-reynolds-formally-requests-expedited-presidential-major-disaster-declaration
