Floods are one of the most common hazards in the United States, and constitute a real danger in Arizona. Floods can be local, impacting a neighborhood or community, or very large, affecting entire river basins and multiple states. Arizona has experienced flooding incidents of sufficient magnitude to prompt presidential and/or gubernatorial disaster declarations.
Some floods develop slowly, while flash floods can develop in just a few minutes and without visible signs of rain. 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. Flash flooding is responsible for more fatalities—40 in Arizona since 1996—than any other thunderstorm-associated hazard.
Overland flooding 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 small streams, gullies, creeks, culverts, dry streambeds or low-lying ground that appear harmless in dry weather can flood.
Before a 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.
- Build an emergency kit and make a family communications plan.
- 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.
- Install "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.
- Flood risk is 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.
- Flood losses are not typically covered under renter and homeowner’s insurance policies.
- FEMA manages the National Flood Insurance Program (NFIP), which makes federally-backed flood insurance available in communities that agree to adopt and enforce floodplain management ordinances to reduce future flood damage.
- Flood-hazard maps have been created to show the flood risk for your community. Talk to your insurance provider about the type of flood insurance coverage you will need.
- 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 an identified flood-prone area.
- Find out if your home or business is at risk for flood and educate yourself on the impact a flood could have on you and your family.
- Contact the NFIP. The NFIP offers flood insurance to homeowners, renters, and business owners if their community participates in the NFIP. To find out more about the NFIP visit www.FloodSmart.gov.
Driving: Flood Facts
- 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.
- Do not attempt to drive through a flooded road. The depth of water is not always obvious. The road bed may be washed out under the water, and you could be stranded or trapped.
- Do not drive around a barricade or try to take short cuts. Stick to designated evacuation routes.
- Be especially cautious driving at night when it is harder to recognize flood dangers.
During a Flood
- 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.
- Be aware of stream, 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.
- Be prepared to evacuate.
- Secure your home. If you have time, bring in outdoor furniture. Move essential items to an 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.
- Follow orders to evacuate.
- 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.
- Do not camp or park your vehicle along streams, rivers or creeks, particularly during threatening conditions.
After a Flood
- Use local alerts and warning systems to get information and expert advice.
- Avoid moving water.
- Stay away from damaged areas unless your assistance has been requested by police, fire, or a relief organization.
- Stay off the roads and out of the way of emergency workers.
- Listen for local warnings and information.
- Return home only when authorities indicate it is safe.
- 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. Avoid walking or driving through it.
- Be aware of areas where floodwaters have receded. Roads may have weakened.
- 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.
- Look after yourself and your family as you begin the recovery process.
- Avoid floodwaters; water may be contaminated by oil, gasoline or raw sewage.
- Service damaged septic tanks, cesspools, pits and leaching systems as soon as possible. Damaged sewer systems are serious health hazards.
- Listen for news reports to learn whether the community’s water supply is safe to drink.
- Clean and disinfect everything that got wet. Mud left from floodwaters can contain sewage and chemicals.
- Turn off the electricity at the main breaker or fuse box, even if the power is off in your community. That way, you can decide when your home is dry enough to turn it back on.
- Contact your insurance agent to discuss claims.
- Listen to your radio for information on assistance that may be provided by the state or federal government or other organizations.
- If you hire cleanup or repair contractors, check references and be sure they are qualified to do the job. Be wary of people who drive through neighborhoods offering help in cleaning up or repairing your home.
- Know the emergency plans for your area.
- 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.
- Research additional information about floods, beginning with the following resources.
- Repairing Your Flooded Home
- After a Flood: The First Steps
- Homeowner’s Guide to Retrofitting: Six Ways to Protect Your House from Flooding
- About the Flood: Elevating Your Floodprone House
- Protecting Building Utilities From Flood Damage
- National Weather Service
- U.S. Environmental Protection Agency
- Centers for Disease Control and Prevention