The I-94 derecho was a progressive derecho that moved through the Upper

Mississippi Valley The Mississippi River is the List of longest rivers of the United States (by main stem), second-longest river and chief river of the second-largest Drainage system (geomorphology), drainage system in North America, second only to the Hudson B ...

on July 19, 1983. It is so called because the derecho moved through

Minnesota Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over to ...

and

Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...

with I-94 as its axis. The derecho formed as an area of disturbed weather in eastern

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...

moved eastward. It moved into northwestern

North Dakota North Dakota () is a U.S. state in the Upper Midwest, named after the Native Americans in the United States, indigenous Dakota people, Dakota Sioux. North Dakota is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north a ...

at around 7a.m. CDT forming a small bow echo. Williston and

Minot Minot ( ) is a city in and the county seat of Ward County, North Dakota, Ward County, North Dakota, United States, in the state's north-central region. It is most widely known for the Minot Air Force Base, Air Force base approximately north of ...

reported winds up to . Further development formed two and three bow echo segments as the storm moved into

. Winds of were recorded at the

Alexandria Alexandria ( or ; ar, ٱلْإِسْكَنْدَرِيَّةُ ; grc-gre, Αλεξάνδρεια, Alexándria) is the second largest city in Egypt, and the largest city on the Mediterranean coast. Founded in by Alexander the Great, Alexandria ...

airport. The winds damaged and destroyed hangars. It continued southeast and arrived at

Minneapolis, Minnesota Minneapolis () is the largest city in Minnesota, United States, and the county seat of Hennepin County. The city is abundant in water, with thirteen lakes, wetlands, the Mississippi River, creeks and waterfalls. Minneapolis has its origins ...

at around 4p.m. CDT and left 250,000 people without power. Trees were blown over and buildings damaged as the derecho raced through

. A meteorologist working at the

University of Wisconsin–Madison A university () is an educational institution, institution of higher education, higher (or Tertiary education, tertiary) education and research which awards academic degrees in several Discipline (academia), academic disciplines. Universities ty ...

saw the derecho approach from the southeastern shore of Lake Mendota near

Madison, Wisconsin Madison is the county seat of Dane County and the capital city of the U.S. state of Wisconsin. As of the 2020 census the population was 269,840, making it the second-largest city in Wisconsin by population, after Milwaukee, and the 80th-lar ...

. On the university's campus, the windows were blown out of the second and third stories of the library. Tiles from the roof were blown off and landed several blocks to the southeast. The strong winds resulted in waves on Lake Mendota. The derecho started moving into northern

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolita ...

at around 9p.m. CDT.

National Weather Service The National Weather Service (NWS) is an Government agency, agency of the Federal government of the United States, United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weathe ...

meteorologist Richard Koeneman recorded observations in his weather diary, noting that the evening was "warm and humid", but that the temperature dropped in 20 minutes ( from 9:30 to 9:50 as the derecho passed. He also wrote that the wind had gusted to around . The derecho winds were still strong as it moved into northwestern side of

Chicago (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name ...

. A wind gust of {{convert, 69, mph was recorded at

O'Hare International Airport Chicago O'Hare International Airport , sometimes referred to as, Chicago O'Hare, or simply O'Hare, is the main international airport serving Chicago, Illinois, located on the city's Northwest Side, approximately northwest of the Chicago Loop, ...

. The derecho finally died out over northwestern

Indiana Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th s ...

at around midnight on July 20. The storm was responsible for 34 injuries, including 12 from mobile homes being overturned and 8 from falling trees.

References

External links

NOAA Page on the I-94 Derecho
1983 meteorology 1983 natural disasters in the United States Derechos in the United States Natural disasters in Illinois Natural disasters in Minnesota Natural disasters in Wisconsin July 1983 events in the United States

See also

References

External links