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Floods
Floods are one of the most 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, all floods are not alike. 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.
How can I protect myself from a flood?
Flood: Know Your Terms
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.
Before a Flood
To prepare for a flood, you should:
• 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, floodwalls) to stop floodwater
from entering the building.
• Seal walls in basements with waterproofing compounds to avoid
seepage.
The smartest thing you can do to prepare for floods is purchase flood
insurance.
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 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.
• 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 quickly swept away.
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.
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.