Today in Iowa history: Deadly 1984 storm spun off record number of tornadoes

Virginia Barreda, Des Moines Register
·2 min read

Today (June 7) in 1984, at least 21 tornadoes touched down in Iowa during what meteorologists called a "severe weather outbreak" — marking what was then a record number of tornadoes in a single event, according to the National Weather Service Des Moines and Des Moines Register archives.

The tornadoes swept through nearly every county in western and southern Iowa, including Polk, twisting and flattening buildings, uprooting trees and downing power lines in their wake, Register reporters wrote in the days following the storm, which left at least four people dead and 91 people injured.

Subsequent reports from the Register showed as many as 35 tornadoes were recorded during the weather event.

On June 7, 1984, at least 21 tornadoes touched down in Iowa during what meteorologists called a "severe weather outbreak" — marking the highest number of tornadoes in during one event at the time, according to officials from the National Weather Service Des Moines.
On June 7, 1984, at least 21 tornadoes touched down in Iowa during what meteorologists called a "severe weather outbreak" — marking the highest number of tornadoes in during one event at the time, according to officials from the National Weather Service Des Moines.

NWS officials said one tornado produced a "nearly-continuous damage track" for 127 miles over a 3-hour span, barreling from northern Missouri into Iowa just southeast of Lamoni and heading northeast before finally lifting near Sigourney.

This tornado was responsible for two deaths and 63 injuries, according to the weather service.

Of the 21 tornadoes spotted on June 7, 1984, 16 were rated F2 on the Fujita Scale, which measures tornado damage intensity, marking the most F2 tornadoes reported in a single day.

That is, until Iowa's historic Dec. 15 derecho when there were 21 EF-2 tornadoes. Enhanced Fujita Scale or EF Scale (a revised version of the F-Scale) is used to assign a tornado a rating based on estimated wind speeds and related damage, according to the National Weather Service. EF-2s  can travel between speeds of 111-135 mph.

National Weather Service confirmed the derecho spawned more than 60 tornadoes across the state, enough to make it the most tornadoes in any single day in the state's historical record, and more than seven times the total number of tornadoes to take shape in December in Iowa since 1950.

The state's previous single-day record, set on Aug. 31, 2014, was 35. According to the National Weather Service, only six tornadoes had been recorded in any December in Iowa between 1950 and 2020.

The historic weather event also marked the first December derecho in U.S. history, and the state's second in as many years.

Virginia Barreda is a trending and general assignment reporter for the Des Moines Register. She can be reached at vbarreda@gannett.com. Follow her on Twitter at @vbarreda2. 

This article originally appeared on Des Moines Register: Today in Iowa history: Deadly tornadoes tear through the state in 1984