- FLOODS -

Floods are one of the most common hazards in the world. Flood effects can be local, impacting a community, or very large, affecting entire river basins and multiple states. Many conditions can result in a flood: broken levees, hurricanes, rapid accumulation of rainfall, and outdated or clogged drainage system.

Be aware of flood hazards no matter where you live, especially if you live in a low-lying area, near water or downstream from a dam. Even very small streams, creeks, gullies, dry streambeds, culverts, or low-lying ground that appears harmless in dry weather can flood.

There are few places on Earth where people need not be concerned about flooding. Any place where rain falls is vulnerable, although rain is not the only impetus for flood.

A flood occurs when water overflows or inundates land that's normally dry. This can happen in a multitude of ways. Most common is when rivers or streams overflow their banks. Excessive rain, a ruptured dam or levee, rapid ice melting in the mountains, or even an unfortunately placed beaver dam can overwhelm a river and send it spreading over the adjacent land, called a floodplain. Coastal flooding occurs when a large storm or tsunami causes the sea to surge inland.

Most floods take hours or even days to develop, giving residents ample time to prepare or evacuate. Others generate quickly and with little warning. These flash floods can be extremely dangerous, instantly turning a babbling brook into a thundering wall of water and sweeping everything in its path downstream.

Disaster experts classify floods according to their likelihood of occurring in a given time period. A hundred-year flood, for example, is an extremely large, destructive event that would theoretically be expected to happen only once every century. But this is a theoretical number. In reality, this classification means there is a one-percent chance that such a flood could happen in any given year. Over recent decades, possibly due to global climate change, hundred-year floods have been occurring worldwide with frightening regularity.

Moving water has awesome destructive power. When a river overflows its banks or the sea drives inland, structures poorly equipped to withstand the water's strength are no match. Bridges, houses, trees, and cars can be picked up and carried off. The erosive force of moving water can drag dirt from under a building's foundation, causing it to crack and tumble.

In the United States, where flood mitigation and prediction is advanced, floods do about $6 billion worth of damage and kill about 140 people every year. A 2007 report by the Organization for Economic Cooperation and Development found that coastal flooding alone does some $3 trillion in damage worldwide. In China's Yellow River valley, where some of the world's worst floods have occurred, millions of people have perished in floods during the last century.

When floodwaters recede, affected areas are often blanketed in silt and mud. The water and landscape can be contaminated with hazardous materials, such as sharp debris, pesticides, fuel, and untreated sewage. Potentially dangerous mold blooms can quickly overwhelm water-soaked structures. Residents of flooded areas can be left without power and clean drinking water, leading to outbreaks of deadly waterborne diseases like typhoid, hepatitis A, and cholera.

But flooding, particularly in river floodplains, is as natural as rain and has been occurring for millions of years. Famously fertile floodplains like the Mississippi Valley in the American Midwest, the Nile River valley in Egypt, and the Tigris-Euphrates in the Middle East have supported agriculture for millennia because annual flooding has left millions of tons of nutrient-rich silt deposits behind.

Most flood destruction is attributable to humans' desire to live near picturesque coastlines and in river valleys. Aggravating the problem is a tendency for developers to backfill and build on wetlands that would otherwise act as natural flood buffers.

Many governments mandate that residents of flood-prone areas purchase flood insurance and build flood-resistant structures. Massive efforts to mitigate and redirect inevitable floods have resulted in some of the most ambitious engineering efforts ever seen, including New Orleans's extensive levee system and massive dikes and dams in the Netherlands. And highly advanced computer modeling now lets disaster authorities predict with amazing accuracy where floods will occur and how severe they're likely to be.

Flash Flood or Flood Watch:

Indicates flash flooding or flooding is possible within the designated watch area. When a watch is issued, be alert and ready to take action.

Flash Flood or Flood Warning: Flash flooding or flooding has been reported or is imminent. You should take necessary precautions and actions at once.

Act Now To Be Prepared

Learn the safest route from your home or business to high, safe ground should you have to leave in a hurry. Develop and practice a 'family escape' plan and identify a meeting place if family members become separated. Make an itemized list of all valuables including furnishings, clothing and other personal property. Keep the list in a safe place.

Stockpile emergency supplies of canned food, medicine and first aid supplies and drinking water. Store drinking water in clean, closed containers.

Plan what to do with your pets.

Have a portable radio, flashlights, extra batteries and emergency cooking equipment available.

Keep your automobile fueled. If electric power is cut off, gasoline stations may not be able to pump fuel for several days. Have a small disaster supply kit in the trunk of your car.

Find out how many feet your property is above and below possible flood levels. When predicted flood levels are broadcast, you can determine if you may be flooded. Keep materials like sandbags, plywood, plastic sheeting and lumber handy for emergency water-proofing. During the Flood.

Monitor the National Oceanic & Atmospheric Administration's (NOAA) Weather Radio or your local radio and TV station broadcasts for information.

If local officials advise evacuation, do so promptly.

If directed to a specific location, go there.

Know where the shelters are located.

Bring outside possessions inside the house or tie them down securely. This includes lawn furniture, garbage cans, and other movable objects.

If there is time, move essential items and furniture to upper floors in the house. Disconnect electrical appliances that cannot be moved. DO NOT touch them if you are wet or standing in water.

If you are told to shut off water, gas, or electrical services before leaving, do so.

Secure your home: lock all doors and windows. Travel With Care

Leave early to avoid being marooned on flooded roads. Make sure you have enough fuel for your car.

Follow recommended routes. DO NOT sightsee.

As you travel, monitor NOAA Weather Radio and local radio broadcasts for the latest information.

Watch for washed-out roads, earth-slides, broken water or sewer mains, loose or downed electrical wires, and falling or fallen objects.

Watch for areas where rivers or streams may suddenly rise and flood, such as highway dips, bridges, and low areas. DO NOT attempt to drive over a flooded road. Turn around and go another way.

DO NOT underestimate the destructive power of fast-moving water. Two feet of fast-moving flood water will float your car. Water moving at two miles per hour can sweep cars off a road or bridge.

If you are in your car and water begins to rise rapidly around you, abandon the vehicle immediately. After the Flood.

Listen to the radio or TV for instructions from local officials.

Wait until an area has been declared safe before entering it. Be careful driving, since roads may be damaged and power lines may be down.

Before entering a building, check for structural damage. Turn off any outside gas lines at the meter or tank. Let the building air out to remove foul odors or escaping gas. Upon entering the building, use a battery-powered flashlight. DO NOT use an open flame as a source of light. Gas may be trapped inside.

When inspecting the building, wear rubber boots and gloves.

Watch for electrical shorts and live wires before making certain the main power switch is off.

DO NOT turn on electrical appliances until an electrician has checked the system and appliances.

Throw out any medicine or food that has had contact with flood waters.

Test drinking water for portability. Wells should be pumped out and water tested for drinking.

If the public water system is declared 'unsafe' by health officials, water for drinking and cooking should be boiled vigorously for 10 minutes.

Shovel out mud with special attention to cleaning heating and plumbing systems.

Flooded basements should be drained and cleaned as soon as possible. Structural damage can occur if drained too quickly. When surrounding waters have subsided, begin draining the basement in stages, about 1/3 of the water volume each day.

The Hidden Danger - Low-Water Crossing

Nearly half of all flash flood fatalities are vehicle related! When driving your automobile during flood conditions, look out for flooding at highway dips, bridges and low areas.

Even the largest and heaviest of vehicles will float. Two feet of water will carry most cars away.

As little as six inches of water may cause you to lose control of your vehicle. Do not drive through flowing water!

A hidden danger awaits motorists where a road without a bridge dips across a creek bed.

Motorists develop false confidence when they normally or frequently pass through a dry low-water crossing.

Road beds may have been scoured or even washed away during flooding creating unsafe driving conditions.

Those who repeatedly drive through flooded low-water crossings may not recognize the dangers of a small increase in the water level.

Driving too fast through low water will cause the vehicle to hydroplane and lose contact with the road surface. Visibility is limited at night increasing the vulnerability of the driver to any hidden dangers.

Heed all flood and flash flood watches and warnings. Remain aware of road conditions!