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 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 populated areas.

Be aware of flood hazards no matter where you live or work, but especially if you are in low-lying areas, or near water. Even very small streams, gullies, creeks, culverts, dry streambeds or low-lying ground that appear harmless in dry weather can flood.

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Before

Cornwall is subject to flooding hazards. Its 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.

Note standard homeowners insurance does not cover flooding. The lower the degree of risk, the lower the flood insurance premium. For information pertaining to flood insurance, flood maps and other flooding risks visit FloodSmart.gov.

To prepare for a flood, you should:

• Build an Emergency Supply Kit, see our Build A Kit information pertaining to Flooding under the Prepare section of our site.
• Avoid building in a floodplain unless you elevate and reinforce your home. Or take steps to establish water barriers.
• Elevate the furnace, water heater and electric panel in your home.
• Consider installing "check valves" to sewage and sanitation plumbing to prevent flood water from backing up into the drains of your home.
• If possible and reasonable, construct barriers to stop floodwater from entering the building and seal walls in basements with waterproofing compounds.

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During

If a flood is imminent.

Listen to the radio, television or emergency officials 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 stream, drainage channels, 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 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.

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, when water is not moivng or not more than a few inches deep. You and the vehicle can be swept away quickly. If your vehicle is trapped in rapidly moving water, stay in the vehicle. If the water is rising inside the vehicle, seek refuge on the roof.
• Do not camp or park your vehicle along streams, rivers or creeks, particularly during threatening conditions.

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After

Many dangers still exist, following the aftermath of a flood. Important things to keep in mind:

• 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, emergency management, or a relief organization.
• Emergency workers will be assisting people in flooded areas. The best way you can help them is by staying off the roads and out of the way. You may be able to help or volunteer through a local program or relief organization
• 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. For your safety find a safer, clear route if possible.
• 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 items that may cause injury, and its also slippery.
• 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 and general structure.

Staying Healthy
A flood can cause physical hazards and emotional stress. You need to look after yourself and your family as you focus on cleanup and repair.

Keep in mind that after a flood the water may be contaminated by oil, gasoline or raw sewage. It is best to 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 communitys water supply is safe to drink and if there are boil water advisories. Clean and disinfect everything that got wet. Mud left from floodwaters can contain sewage and chemicals. Please remember to rest often and eat well. Keep a manageable schedule to reduce strain and stress. Make a list and do jobs one at a time. This is effectively managing your resources and energy by taking baby steps. Discuss your concerns with others and seek help.

Cleaning Up and Repairing Your Home:

• 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.
• You can ask for a guide on how to repair your flooded home, available from the Cornwall emergency manager. It will include tips and guidance on: how to enter your home safely, how to protect your home and belongings from further damage, how to record damage to support insurance claims and requests for assistance, how to check for gas or water leaks and how to have service restored, how to clean up appliances, furniture, floors and other belongings. Additionally The Red Cross can provide you with a cleanup kit: mop, broom, bucket, and cleaning supplies.
• Listen to your radio for information on assistance that may be provided by the state or federal government or other organizations.
• If you decide to 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. Often times these are scams.

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After

Tropical Storms and Hurricanes

Hurricanes pack a triple punch: high winds, heavy rain, and flying debris. They can cause storm surges to coastal areas, as well as create heavy rainfall which in turn causes flooding hundreds of miles inland.

When hurricanes weaken into tropical storms, they generate rainfall and flooding that can be especially damaging since the rain collects in one place.

Spring Thaw

During the spring, frozen land prevents melting snow or rainfall from seeping into the ground. Each cubic foot of compacted snow contains gallons of water and once the snow melts, it can result in the overflow of streams, rivers, and lakes. Add spring storms to that and the result is often serious spring flooding.

Heavy Rains

Several areas of the country are at heightened risk for flooding due to heavy rains. The Northeast is at high risk due to heavy rains produced from Nor easters. This excessive amount of rainfall can happen throughout the year, putting property at risk.

Flash Floods

Flash floods are the #1 weather related killer in the U.S. since they can roll boulders, tear out trees, and destroy buildings and bridges. A flash flood is a rapid flooding of low lying areas in less than six hours, which is caused by intense rainfall from a thunderstorm or several thunderstorms. Flash floods can also occur from the collapse of a man made structure or ice dam.

New Development

Construction and development can change the natural drainage and create brand new flood risks. That is because new buildings, parking lots, and roads mean less land to absorb excess precipitation from heavy rains, hurricanes, and tropical storms.

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Terminology

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 immediately.