Many people are familiar with flooding due to heavy rainfall, but floods can occur in a number of different ways. Melting snow, a broken levee or dam and even powerful ocean waves hitting the shore have the ability to cause flooding. Floods can develop rapidly, or over a long period of time, and are the most common weather-related natural disaster.

Devastating and unpredictable, flash floods are the most dangerous types of floods. They are usually caused by excessive rainfall over a short period of time. The excess water sweeps through river beds and streets, collecting everything in its path. This type of flood can cause fast moving torrents, capable of carrying away cars and even homes. Areas with little to no vegetation can be especially vulnerable to flash floods because the excess water can’t be absorbed quickly enough to prevent flooding.

Other types of floods include river, coastal, inland and storm surge. The National Weather Service categorizes floods in in following ways:

  • Minor Flooding — minimal or no property damage, but possibly some public threat or inconvenience.
  • Moderate Flooding — some inundation of structures and roads near streams. Some evacuations of people and/or transfer of property to higher elevations are necessary.
  • Major Flooding — extensive inundation of structures and roads. Significant evacuations of people and/or transfer of property to higher elevations.

Safety Tips

All floods have the potential to lead to dangerous conditions. It’s important to take flood warnings seriously and prepare accordingly. Below are a some tips to help keep you safe during a flood:

  • Avoid walking or driving through flood waters.
  • Do not drive over bridges that are over fast-moving floodwaters. Floodwaters can scour foundation material from around the footings and make the bridge unstable.
  • Just 6 inches of moving water can knock you down, and one foot of moving water can sweep your vehicle away.
  • If there is a chance of flash flooding, move immediately to higher ground.
  • If floodwaters rise around your car but the water is not moving, abandon the car and move to higher ground. Do not leave the car and enter moving water.
  • Avoid camping or parking along streams, rivers, and creeks during heavy rainfall. These areas can flood quickly and with little warning.
View more flood safety tips and resources from the National Weather Service ›