Flooding typically occurs when prolonged rain falls over several days, when intense rain falls over a short period of time, or when an ice or debris jam causes a river or stream to overflow onto the surrounding area.

Flooding in Hamburg, Iowa, in 2019.
Flooding in Hamburg, Iowa, in 2019.

A flood is the most common natural disaster in the world. Floods can happen during heavy rains, when snow melts quickly, or when dams or levees break.

Flash floods are the most dangerous kind of floods, because they combine the destructive power of a flood with extraordinary speed. Flash floods occur when heavy rainfall exceeds the ability of the ground to absorb it.           

You should be aware of flood hazards no matter where you live, but especially if you live in a low-lying area, near water or downstream from a dam. Even very small streams, gullies, creeks, culverts, dry streambeds, or low-lying ground that appear harmless in dry weather can flood. Every state is at risk for flooding.

Flood mitigation

Mitigation includes any activities that prevent an emergency, reduce the chance of an emergency happening, or lessen the damaging effects of unavoidable emergencies. Investing in mitigation steps now such as constructing levees and purchasing flood insurance will help reduce the amount of structural damage to your home and financial loss from building and crop damage should a flood or flash flood occur.

What to do before, during and after a flood

Before a flood
  • Sign up for local alerts or Alert Iowa, enable WEA alerts on your mobile phone.
  • Find out if you live in an area that has a flood risk from your local emergency management office or visit FEMA’s Flood Map Service Center for more information.
  • If you live in a frequently flooded area, stockpile emergency building materials. These include plywood, plastic sheeting, lumber nails, hammer and saw, pry bar, shovels, and sandbags.
  • Keep important documents in a dry, safe place such as a fireproof, waterproof container, and create password-protected digital copies.
  • Protect your property. Move valued items to higher levels. Elevate critical utilities. Install a back valve and a battery-operated sump pump. Declutter drains and gutters. Use sandbags to create a flood barrier. As a last resort, use large corks or stoppers to plug showers, tubs, or basins.
  • Plan and practice an evacuation route. Contact the local emergency management office or local Red Cross chapter for a copy of the community flood evacuation plan. This plan should include information on the safest routes to shelters. Individuals living in flash flood areas should have several alternative routes.
  • Develop a family emergency communication plan and have disaster supplies on hand.
  • Learn about the National Flood Insurance Program (NFIP). Ask your insurance agent about flood insurance. Most homeowners policies do not cover flood damage.
  • Catalog your belongings. Take photos of rooms, furniture, books, appliances, computer equipment, DVDs, and other items of value. Keep your catalog or “inventory list” in a safe place.
During a flood watch
  • Pay attention to the news, and know the latest storm information.
  • Evacuate immediately when ordered to. Do not underestimate the threat of flooding by failing to evacuate when it is safe to do so. Take critical supplies and documents with you when you evacuate.
  • Move to higher ground or the highest level of a building to avoid becoming trapped by rising floodwater but do not climb into a closed attic.
  • Do not attempt to cross floodwaters. Floodwater can pose a drowning risk for everyone — regardless of their ability to swim.
  • Do not drive through floodwaters. The depth of the water is not always obvious and just a foot of moving water can sweep a vehicle — even a sports utility vehicle — off the road.
  • Never drive around barriers blocking a flooded road.
During a flood

If Indoors

  • Turn on battery-operated radio or television to get the latest emergency information.
  • Get your pre-assembled emergency supplies.
  • If told to leave, do so immediately.

If Outdoors

  • Climb to high ground and stay there.
  • Avoid walking through any floodwaters. If it is moving swiftly, even water six inches deep can sweep you off your feet.

In A Car

  • If you come to a flooded area, turn around and go another way.
  • If your car stalls, abandon it immediately and climb to higher ground. Many deaths have resulted from attempts to move stalled vehicles.

During an Evacuation

  • If advised to evacuate, do so immediately.
  • Evacuation is much simpler and safer before flood waters become too deep for ordinary vehicles to drive through.
  • Listen to a battery-operated radio for evacuation instructions.
  • Follow recommended evacuation routes; shortcuts may be blocked.
  • Leave early enough to avoid being trapped by flooded roads.
After the flood

Assessing the Situation

  • Flood dangers do not end when the water begins to recede. Listen to a radio or television and don’t return home until authorities indicate it is safe to do so.
  • Do not assume your drinking water is safe to use or consume after a flood. Check with your local health department.     
  • Stay away from floodwater. It may contain hazards, including sharp objects, downed power lines, sewage, bacteria, chemicals, diseased insects and wild or stray animals.
  •  Be careful when going outdoors after a flood. Be alert for downed or unstable trees, utility poles and power lines.  
  • Do not touch electrical equipment if it is wet or if you are in standing water.
  • When entering buildings, use extreme caution.
    • Wear sturdy shoes and use battery-powered lanterns or flashlights when examining buildings.
    • Examine walls, floors, doors, and windows to make sure that the building is not in danger of collapsing.
    • Watch out for animals that may have come into your home with the flood waters.
    • Watch for loose plaster and ceilings that could fall.
    • Take pictures of the damage–both to the house and its contents for insurance claims.
  • Look for fire hazards.
    • Broken or leaking gas lines
    • Flooded electrical circuits
    • Submerged furnaces or electrical appliances
    • Flammable or explosive materials coming from upstream
  • Throw away food – including canned goods – that has come in contact with flood waters.
  • Pump out flooded basements gradually (about one-third of the water per day) to avoid structural damage.
  • Service damaged septic tanks, cesspools, pits, and leaching systems as soon as possible. Damaged sewage systems are health hazards.

Iowa Disaster History - Iowa Flood of 1993

The Great Flood of 1993

17

fatalities

10,000

people evacuated

21,000

homes damaged or destroyed

$2.7B

in damage

Iowa Disaster History

Great Flood of 1993

The flood of 1993 is one of the most defining natural disasters in Iowa history. When President Clinton surveyed the damage he stated, “I have never seen anything on this scale before." Video: KCCI 8