Iowa Tornado & Hail Guide

Iowa averages approximately 50 tornadoes per year. The state straddles the northern edge of Tornado Alley, and its combination of warm, humid summer air and proximity to the jet stream makes it prone to significant severe weather outbreaks from late spring through early summer.

Iowa Tornado Season

Iowa’s tornado season runs May through August, with June as the peak month. Central and southern Iowa see the most frequent tornado activity. The Quad Cities metro area (eastern Iowa/western Illinois border) and the Des Moines metro have experienced multiple significant tornado events.

Iowa Hail Season

Significant hail events occur across Iowa from April through August. Central Iowa — particularly the Des Moines metro — has seen repeated large hail events causing hundreds of millions in insured losses. Iowa corn and soybean crops are also significantly affected by severe hail.

Historical Significant Events

• 1882 Grinnell tornado (F5): One of the most historically documented tornadoes in U.S. history; 117 fatalities.
• 2008 Parkersburg EF5: Struck the small town of Parkersburg in Butler County on May 25, 2008, killing 9. One of the last confirmed EF5 tornadoes in U.S. history.
• 2008 Iowa City EF2: Struck the University of Iowa campus area during a major June outbreak.
• 2011 Mapleton EF4: Significant damage to the western Iowa town of Mapleton; no fatalities.

Regional NWS Offices for Iowa

| Region | WFO | Website |

|——–|—–|———|

| Central Iowa (Des Moines) | NWS Des Moines | weather.gov/dmx |

| Eastern Iowa/Quad Cities | NWS Quad Cities | weather.gov/dvn |

| Northeast Iowa (La Crosse area) | NWS La Crosse | weather.gov/arx |

| Western Iowa (Sioux City) | NWS Sioux Falls (shared) | weather.gov/fsd |

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*FindTheTornado.com does not perform inspections, repairs, or insurance work. Data from NOAA NCEI and NWS.*