This Day in Weather History June 12
National Oceanic and Atmospheric Administration
2001: Several rounds of severe thunderstorms and heavy rainfall affected portions of central and northwestern Iowa through much of the day. An outflow boundary lying roughly along the Interstate 80 corridor in central Iowa was the focus for multiple rounds of training thunderstorms that developed just before sunrise and persisted into the early afternoon. One particularly severe cluster of thunderstorms produced very large hail across western portions of the Des Moines metro area, with golf ball to baseball sized hail falling for up to 25 minutes in West Des Moines, Waukee, Clive, and Urbandale. There was significant damage to thousands of homes and vehicles, and several large car dealerships hit with damage in the hundreds of thousands of dollars at each one. Some cars has their windows completely broken out and roofs badly dented. Further east around Grinnell and Montezuma up to 4 inches of rain fell along with golf ball sized hail that drifted to more than 2 feet deep in some places. In the later morning hours heavy rain became the dominant threat with flash flooding reported across much of Greene, Boone, Dallas, and Story counties and numerous roads closed due to high water. Later in the evening additional thunderstorms developed across far northwestern Iowa, again training over the same areas for several hours. These storms produced large hail as well as several weak tornadoes, straight line wind gusts in excess of 70 mph, and more flash flooding. Some locations were struck repeatedly, especially across Lyon, Osceola, and Dickinson counties. There were reports from the town of George of baseball sized hail, followed an hour and a half later by more baseball sized hail along with severe winds and a weak tornado, followed again 40 minutes later by 2.5 inch hail, more severe winds, and flash flooding.
1994: Severe thunderstorms in northwestern Iowa produced tornadoes at Lake Park and Le Mars with the latter damaging about 120 buildings. Strong winds of 60 to 80 mph around Spirit Lake threw a sail boat into a tree along the shoreline. Storms also produced very heavy rain and flash flooding in Lyon, Emmet, Dickinson, and Clay counties. At George in Lyon County 3 inches of rain fell in just 30 minutes.
1947: June was a month of exceptional rainfall and record flooding in many parts of Iowa. After widespread moderate to heavy rain fell across the state on the 1st and again on the 4th-5th one of the most widespread heavy rain events on record in Iowa inundated much of the state from the 11th-12th, with generally more than 4 inches falling in 24 to 30 hours over a swath across southwestern and especially central into northeastern Iowa. Thirty stations across the state reported 4 inches or more of rain during the event. The highest reported storm total rainfall accumulations were 5.92 inches at Van Meter, 5.51 inches at Tripoli, 5.48 inches at Des Moines (making this the second-wettest day on record at that location), 5.37 inches at New Hampton, and 5.34 inches at Waukee. The heavy rain caused record or near record flooding across much of Iowa resulting in significant damage and numerous deaths and injuries.
