Iowa
Iowa's heartland location puts it in the path of tornadoes, derechos, and river floods that reshape the landscape. The August 2020 derecho was the costliest thunderstorm in U.S. history. Cedar Rapids has flooded twice in a generation. The weather here does not do small.
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Know your region
Cedar Rapids, Iowa City, Davenport, Dubuque. The 2008 Cedar Rapids flood was a 500-year event that displaced 24,000 people. The Mississippi River along the eastern border floods regularly. The 2020 derecho leveled trees and grain bins across the corridor.
Primary hazards: flooding, derecho, tornadoes, ice storms
Des Moines, Ames, Marshalltown, Fort Dodge. The 2020 derecho hit central Iowa with 140 mph straight-line winds, causing $11 billion in damage. Tornadoes cross the open terrain regularly. The Des Moines and Raccoon rivers flood after heavy rain.
Primary hazards: derecho, tornadoes, flooding, severe storms
Sioux City, Council Bluffs, the Loess Hills. The Missouri River flooded catastrophically in 2011 and 2019. The 2019 bomb cyclone caused $1.3 billion in damage. Blizzards sweep across the open plains with zero visibility.
Primary hazards: flooding, blizzards, tornadoes, drought
Your hazard profile
Each links to a full guide with during-event protocol, recovery steps, and resources specific to IA.
The August 2020 derecho produced 140 mph winds across central Iowa, causing $11 billion in damage. It was the costliest thunderstorm event in U.S. history. Severe storms with large hail and damaging winds are near-weekly from May through August.
Read the derechos and severe storms guide →
Iowa averages 48 tornadoes per year. The 2024 season produced multiple significant tornadoes. Peak season is May and June, but tornadoes can strike March through November. Basements are the safest shelter.
Read the tornadoes guide →
The 2008 Cedar Rapids flood displaced 24,000 people. The Missouri and Mississippi rivers flood during spring and after heavy rain. The 2019 bomb cyclone caused catastrophic Missouri River flooding. Flash flooding in urban areas develops rapidly.
Read the flooding guide →
Iowa winters bring blizzards with zero visibility, ice storms that knock out power across entire counties, and wind chill values below minus 40 degrees F. Rural roads can be impassable for days.
Read the blizzards and extreme cold guide →
The 2012 drought was the worst since 1988 and caused billions in crop losses. Drought cycles affect Iowa's agricultural economy and rural water supplies. Western Iowa is most drought-prone.
Read the drought guide →
Iowa resources
Iowa Homeland Security and Emergency Management Department. Coordinates disaster response and manages the state's hazard mitigation programs.
Central Iowa forecasts. Severe weather warnings, tornado watches, derecho potential, and winter storm advisories.
University of Iowa's real-time stream monitoring network. River stage data, flood forecasts, and community flood preparedness resources. One of the best state flood monitoring systems in the country.
Statewide information and referral. Disaster recovery resources, energy assistance, food banks, and housing support.
August 10, 2020
On August 10, 2020, a derecho crossed Iowa from west to east in about 45 minutes. Sustained winds of 140 mph flattened millions of acres of corn and soybeans. Trees that had stood for a century snapped like matchsticks. Grain bins crumpled. Power was out for weeks in some areas. The damage totaled $11 billion, making it the costliest thunderstorm event in American history.
Most Iowans had never heard the word "derecho" before that day. Unlike a tornado, which cuts a narrow path, a derecho destroys everything across a front hundreds of miles wide. There was no siren for this. No tornado warning. Just a wall of wind.
For every Iowa household, the derecho lesson is about the storms that do not fit the expected pattern. A safe interior room, a weather radio, and supplies for a week without power are the foundation. The storm you prepare for may not be the storm that arrives.