How to Tell When a Flood Is Coming

The U.S. Geological Survey (USGS) and the National Weather Service (NWS) partner to provide the public with data and warning forecasts for flood events. The USGS deploys stream gauges throughout U.S. inland bodies of water to measure real-time water levels. It records levels every 15 to 60 minutes, transmitting the data to its offices every 1 to 4 hours, increasing the frequency of transmissions in critical events. The USGS shares its data with the NWS, which creates flood advisories, watches and warnings to alert the public of growing flood threats. It disseminates these warnings on its website, via NOAA weather radios and through the news media.

Instructions

• 1

  Monitor daily weather conditions via NOAA weather radio, media, or the Internet. The National Weather Services issues a flood advisory during a flood event or when one is imminent. NWS issues advisories for conditions that are less serious, but that could cause serious inconvenience and threaten property or health without proper precautions. The weather service often issues an advisory and upgrades it to a watch or warning if and when conditions worsen.

• 2

  Make plans for evacuation or other emergency actions if and when the weather service issues, or upgrades to, a watch. A watch signifies a significantly increased risk of flood when its timing or location remain uncertain. NWS releases each watch with enough lead time to allow those in the potential flood area to enact emergency plans. Continue to monitor changing conditions via weather radio, media or the Internet.

• 3

  Take protective action when the NWS issues a flood warning. A warning indicates an imminent or occuring flood threatens property or life. Protective action can mean that you should evacuate or ready your home or business for the flood. Local authorities will issue evacuation instructions, if needed.

• 4

  Return home after authorities have deemed the area safe for return. They will release this information through the media and via NOAA weather radio.