Floods are one of the most common hazards in the United States, however, not all floods are alike. Some floods develop slowly, while others such as flash floods, can develop in just a few minutes and without visible signs of rain. Additionally, floods can be local, impacting a neighborhood or community, or very large, affecting entire river basins and multiple states.
Flash floods can occur within a few minutes or hours of excessive rainfall, a dam or levee failure, or a sudden release of water held by an ice jam. Flash floods often have a dangerous wall of roaring water carrying rocks, mud, and other debris. Overland flooding, the most common type of flooding event typically occurs when waterways such as rivers or streams overflow their banks as a result of rainwater or a possible levee breach and cause flooding in surrounding areas. It can also occur when rainfall or snowmelt exceeds the capacity of underground pipes or the capacity of streets and drains designed to carry flood water away from urban areas.
Be aware of flood hazards no matter where you live or work, but especially if you are in low-lying areas, near water, behind a levee, or downstream from a dam. Even very small streams, gullies, creeks, culverts, dry stream beds, or low-lying ground that appear harmless in dry weather can flood.
Even if you feel you live in a community with a low risk of flooding, remember that anywhere it rains, it can flood. Just because you haven’t experienced a flood in the past, doesn’t mean you won’t in the future. Flood risk isn’t just based on history; it’s also based on a number of factors including rainfall, topography, flood-control measures, river-flow and tidal-surge data, and changes due to new construction and development.
Before a Flood
Store at least one month’s supply of water. Following a flood, clean drinking water may not be available. Your regular water source could be cut-off or compromised through contamination. A normally active person needs at least one gallon of water daily just for drinking however individual needs vary, depending on age, physical condition, activity, diet, and climate.
Store at least one month’s supply of food. Choose salt-free crackers, whole grain cereals, and canned foods with high liquid content. In addition to these, it is highly recommended that you get some MREs (Meals, Ready to Eat), freeze-dried and dehydrated foods which are light, easy to transport, and last up to 25 years. Avoid foods that will make you thirsty. Keep in mind that an average adult consumes 2,000 to 3,000 calories a day.
A basic emergency kit should contain (at least) the following items:
Good quality full tang knife or lockable blade pocket knife
Battery-powered or hand crank radio
Flashlight and extra batteries
First aid kit
Whistle to signal for help
Dust mask to help filter contaminated air
Plastic sheeting and duct tape to shelter-in-place
Emergency blanket or bivy
Emergency tarp or tent
Moist towelettes, garbage bags, and plastic ties for personal sanitation
Wrench or pliers to turn off utilities
Manual can opener for food
Cell phone with chargers, inverter, or solar charger
Your family may not be together when disaster strikes, so it is important to know how you will contact one another, how you will get back together, and what you will do in case of an emergency. Plan places where your family will meet, both within and outside of your immediate neighborhood. Know your community’s warning systems and disaster plans, including evacuation routes.
Avoid building in a floodplain unless you elevate and reinforce your home.
Elevate the furnace, water heater, and electric panel in your home if you live in an area that has a high flood risk.
Consider installing “check valves” to prevent flood water from backing up into the drains of your home.
If feasible, construct barriers to stop floodwater from entering the building and seal walls in basements with waterproofing compounds.
During a Flood
If a flood is likely in your area, you should:
Listen to the radio or television for information.
Be aware that flash flooding can occur. If there is any possibility of a flash flood, move immediately to higher ground. 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 typical warnings such 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 the upper floor.
Turn off utilities at the main switches or valves if instructed to do so. Disconnect electrical appliances. Do not touch electrical equipment if you are wet or standing in water.
If you have to leave your home, remember these evacuation tips:
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, abandon the car and move to higher ground if you can do so safely. You and the vehicle can be swept away quickly.
Do not camp or park your vehicle along streams, rivers, or creeks, particularly during threatening conditions.
After a Flood
Your home has been flooded. Although floodwaters may be down in some areas, many dangers still exist. Here are some things to remember in the days ahead:
Use local alerts and warning systems to get information and expert-informed advice as soon as available.
Avoid moving water.
Stay away from damaged areas unless your assistance has been specifically requested by police, fire, or relief organization.
Emergency workers will be assisting people in flooded areas. You can help them by staying off the roads and out of the way.
Play it safe. Additional flooding or flash floods can occur. Listen for local warnings and information. If your car stalls in rapidly rising waters, get out immediately and climb to higher ground. Return home only when authorities indicate it is safe.
Roads may still be closed because they have been damaged or are covered by water. Barricades have been placed for your protection. If you come upon a barricade or a flooded road, go another way.
If you must walk or drive in areas that have been flooded.
Stay on firm ground. Moving water only 6 inches deep can sweep you off your feet. Standing water may be electrically charged from underground or downed power lines.
Flooding may have caused familiar places to change. Floodwaters often erode roads and walkways. Flood debris may hide animals and broken bottles, and it’s also slippery. Avoid walking or driving through it.
Be aware of areas where floodwaters have receded. Roads may have weakened and could collapse under the weight of a car.
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.