Floods

Flash floods are the deadliest natural disaster in South Dakota. They are caused by often stationary or slow-moving thunderstorms that produce heavy rain over a small area. The Black Hills are especially vulnerable to flash floods, where steep terrain and narrow canyons can funnel heavy rain into small creeks and dry ravines, turning them into raging walls of water. Even on the prairie, normally-dry draws and low spots can fill with rushing water during very heavy rain. Develop flood safety plans for home, work, and wherever you spend time during the summer and be prepared to act quickly if flooding occurs.

Preparations to make at home and work:

  • If you are in a flood-prone area, identify at least one evacuation route to higher ground. Choose a location for family members to meet.
  • Assemble emergency supplies, including: Flashlight and extra batteries, battery-powered radio, weather radio receiver, corded telephone, nonperishable food and water (three gallons per person), first-aid supplies, extra clothing, and bedding. Don't forget special items for family members such as diapers, baby formula, prescription or essential medications, extra eyeglasses or hearing aids, and pet supplies.
  • Know how to shut off electric, gas, and water utilities.
  • Know the county in which you live and nearby rivers and streams. Have a map available so you know where flooding is occurring and if it moving toward your location.
  • Have several methods to receive warning information; such as NOAA Weather Radio, local radio and television stations, cable TV (warnings are not broadcast on satellite TV unless you are watching local stations), and text and e-mail alerts.
  • Understand the terms used to describe flood hazards:
    A Flood Watch means flooding is possible, but is not yet occurring.
    A Flash Flood Warning is issued when dangerous flash flooding will occur quickly.
    A Flood Warning is issued when long-term flooding is imminent or occurring.

When traveling or outdoors:

  • Check the weather forecast before a starting a trip or going outside. Postpone outdoor activities if heavy rain is forecast or a flood watch is in effect.
  • Choose campsites away from creeks and other low-lying areas. Do not stay in areas where your only exit crosses a stream--you may become trapped by rising water.
  • Monitor NOAA Weather Radio or a local radio station for updated forecasts, watches, and warnings.
  • Keep track of the counties, towns, rivers, and creeks along your route so you will know if you are near flooding.
  • Watch for heavy rain upstream of your location or rising water.

If you see rising water or a Flash Flood Warning is issued, get to higher ground immediately!  Follow evacuation instructions, but don't wait for them if you think you are in danger.

  • Turn Around Don't Drown! NEVER drive across flooded roads or bridges they may be washed out. Your vehicle can be swept away by flowing water only a foot or two deep. Be especially cautious at night, when flood waters are difficult to see.
  • Walking or playing in flood waters is dangerous; you can be pushed over by flowing water only six inches deep!

Additional information about Flood Safety is available.

Download the color brochure "Floods and Flash Floods...The Awesome Power" published by the American Red Cross, Federal Emergency Management Agency, and National Weather Service.

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