Floods are common hazards in the United States. Flood effects can be local, impacting a neighborhood or community, or very large, affecting entire river basins and multiple states.
However, floods vary in development and size. Some floods develop slowly, sometimes over a period of days. But flash floods can develop quickly, sometimes in just a few minutes and without any visible signs of rain. Flash floods often have a dangerous wall of roaring water that carries rocks, mud, and other debris and can sweep away most things in its path. Overland flooding occurs outside a defined river or stream, such as when a levee is breached, but still can be destructive. Flooding can also occur when a dam breaks, producing effects similar to flash floods.
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 from this hazard.
Familiarize yourself with these terms to help identify a flood hazard:
- Flood Watch – Flooding is possible. Tune in to NOAA Weather Radio, commercial radio, or television for information.
- Flash Flood Watch – Flash flooding is possible. Be prepared to move to higher ground; listen to NOAA Weather Radio, commercial radio, or television for information.
- Flood Warning – Flooding is occurring or will occur soon; if advised to evacuate, do so immediately.
- Flash Flood Warning – A flash flood is occurring; seek higher ground on foot immediately.
Take Protective Measures
Before a Flood
How to be prepared for a flood:
- Always have a 72 hour (3-day) emergency response kit available to you and each member of your family.
- Consistently be alerted to local weather advisories by using an emergency radio with NOAA auto-alert broadcast capabilities when severe weather threatens your area.
- Avoid building in a floodplain unless you elevate and reinforce your home.
- Elevate the furnace, water heater, and electric panel if susceptible to flooding.
- Install “check valves” in sewer traps to prevent flood water from backing up into the drains of your home.
- Construct barriers (levees, beams, flood walls) to stop floodwater from entering the building.
- Seal walls in basements with waterproofing compounds to avoid seepage.
During a Flood Hazard
If a flood is likely in your area, you should:
- Monitor the radio or television for flood and downpoor warning information.
- In the event of a power outage, which is likely during a flood, have a handcrank radio and handcrank flashlight available.
- Be aware that flash flooding can occur. If there is any possibility of a flash flood, move immediately to higher ground with your 72 hour (3-day) emergency kit, handcrank radio and handcrank flashlight. Do not wait for instructions to move.
- Be aware of streams, drainage channels, canyons, and other areas known to flood suddenly. Flash floods can occur in these areas with or without such typical warnings as rain clouds or heavy rain.
If you must prepare to evacuate you should do the following:
- Secure your home. If you have time, bring in outdoor furniture. Move essential items to an upper floor.
- If instructed to do so, turn off utilities (water and gas) at the main switches or valves with the proper emergency tool.
- Disconnect electrical appliances but do not touch electrical equipment if you are wet or standing in water.
If you have to leave your home remember these evacuation tips:
- Remember that the emergency supplies you have when you leave are all the supplies you may have until you are met by assistance.
- Do not walk through moving water. Six inches of moving water can make you fall. If you have to walk in water, walk where the water is not moving. Use a stick to check the firmness of the ground in front of you.
- Do not drive into flooded areas. If floodwaters rise around your car, ensure you have an On-The-Go 72-hour (3 day) emergency kit, stored in your car and available within arm’s reach, abandon the car and move to higher ground if you can do so safely. Rapid rising floodwaters risks that you and your vehicle can be quickly swept away.
After a Flood
The following are guidelines for the period following a flood:
- Listen for news reports to learn whether the community’s water supply is safe to drink.
- Avoid floodwaters; water may be contaminated by oil, gasoline, or raw sewage. Water may also be electrically charged from underground or downed power lines.
- Avoid moving water.
- Be aware of areas where floodwaters have receded. Roads may have weakened and could collapse under the weight of a car.
- Stay away from downed power lines, and report them to the power company.
- Return home only when authorities indicate it is safe.
- Stay out of any building if it is surrounded by floodwaters.
- Use extreme caution when entering buildings; there may be hidden damage, particularly in foundations.
- Service damaged septic tanks, cesspools, pits, and leaching systems as soon as possible. Damaged sewage systems are serious health hazards.
- Clean and disinfect everything that got wet. Mud left from floodwater can contain sewage and chemicals.
Driving: Flood Facts
The following are important points to remember when driving in flood conditions:
- Six inches of water will reach the bottom of most passenger cars causing loss of control and possible stalling.
- A foot of water will float many vehicles.
- Two feet of rushing water can carry away most vehicles including sport utility vehicles (SUV’s) and pick-ups.
Consider the following facts:
- Flood losses are not covered under homeowners’ insurance policies.
- FEMA manages the National Flood Insurance Program, which makes federally- backed flood insurance available in communities that agree to adopt and enforce floodplain management ordinances to reduce future flood damage.
- Flood insurance is available in most communities through insurance agents.
- There is a 30-day waiting period before flood insurance goes into effect, so don’t delay.
- Flood insurance is available whether the building is in or out of the identified flood-prone area.
For More Information
If you require more information about any of these topics, the following are resources that may be helpful.
After a Flood: The First Steps. L-198. Information for homeowners on preparedness, safety, and recovery from a flood.
Homeowner’s Guide to Retrofitting: Six Ways to Protect Your House from Flooding. L-235. A brochure about obtaining information about how to protect your home from flooding.
Homeowner’s Guide to Retrofitting: Six Ways to Protect Your House from Flooding. FEMA-312. A detailed manual on how to protect your home from flooding.
About the Flood: Elevating Your Floodprone House. FEMA-347. This publication is intended for builders, code officials and homeowners.
Protecting Building Utilities From Flood Damage. FEMA-348. This publication is intended for developers, architects, engineers, builders, code officials and homeowners.