Flooding

Flooding is the most common disaster in the U.S.

Property damage due to flooding exceeds over $1 billion per year in the nation.

 

It takes only 6 inches of water to knock a person down and only 2 feet of water to float a large vehicle.

 

Flooding can happen at any time, anywhere in the United States and can result from heaving rains or failed dams and can trigger other disasters such as mud- and landslides.

 

During a flood:

  • Listen to the radio or television for information and be prepared to evacuate at a moment's notice. 
  • Have an Emergency Supply Kit and Household Disaster Plan in place.
  • Be aware that flash flooding can occur.  If there is any possibility of a flash flood, move to higher ground. 

If you must 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.
  • Stay away from streams, drainage channels, canyons, and other floodwaters.  If you come upon a stream that is above your ankles, stop, turn around and go the other way.
  • If you come upon a flooded road while driving, turn around and go another way. If you are caught on a flooded road and waters are rising rapidly around you, get out of the car quickly and move to higher ground.

Learn more about flood preparedness here.

 

Flooding Caused by Hurricane Ivan | Pittsburgh, PA | September 2004

Causes

 

Spring Thaw

Each cubic foot of compacted snow contains gallons of water that can flood rivers, streams, and creeks upon thawing.

 

Flash Floods

Flash flooding is the #1 weather killer in the United States.  It is defined as rapid flooding that occurs over a period of less than 6 hours.  Flash flooding is powerful enough to uproot trees, washout bridges, destroy houses, and roll boulders.

 

Heavy Rains

Excessive amounts of rain can happen any time, any where, but some areas are more likely to see heavy rains; the Northwesten U.S. is susceptible to the effects of La Niña, while the Northeast is prone to rains from Nor'easterns.

 

New Development

The growth of businesses and homes in an area can change the landscape and natural drainage of water from rain or melting snow.

 

Tropical Storms and Hurricanes

In 2001, Tropical Storm Allison produced more than 30 inches of rain in Houston in just a few days.  This resulted in the flooding of 70,000 houses and destroyed 2,744 homes

 

Levees and Dams

While dams and levees are designed to protect an area from flooding, sometimes they can cause more damage when they fail or are overtopped than if they weren't there.

 

West Coast Threats

The rainy season on the West Coast lasts from November to April which can produce heavy rains resulting in the overtopping of their thousands-of-miles-system of dams and levees.  In addition, large wildfires have changed the landscape causing mudflows that can exceed 10 mph.

Terms

Familiarize yourself with these terms to help identify a flood hazard...

 

  • Flood Watch - Flooding is possible; tune into your local tv or radio stations for more information
  • Flash Flood Watch - Flash flooding is possible; tune into your local tv or radio stations for more information
  • Flood Warning - Flooding will occur soon or is occuring; be prepared to evacuate if advised
  • Flash Flood Warning - Flash flooding is occuring; seek higher ground immediately; do not attempt to pass through flood waters

 

Hurricane Katrina Flooding | New Orleans, LA