What you need to know about flood and flash flood alerts
Last updated: October 2023
Rain can occur anywhere, which means everyone is at risk for floods or flash floods. But whether flooding occurs slowly or quickly, it can cause costly damage to homes and businesses and may put you and your family in danger. By paying close attention to weather notifications and acting quickly, you can help keep you and your family safe. Read on to learn what you need to know about the weather emergency notifications that are issued for floods and flash floods:
What is the difference between a flood and a flash flood?
The National Weather Service (NWS) says a flood is typically caused by rising water from a river or stream and can last for days or weeks. A flash flood, on the other hand, is typically the result of heavy rain and happens quickly — usually within three to six hours of heavy rainfall. While floods can happen anywhere, people who live in certain places may be at a higher risk, says the NWS. This includes those who live in densely populated areas or near rivers, streams and dams.
Flood watch vs. flash flood watch
If your local area is under a flood watch, it means weather conditions are favorable for a flood to occur, says the NWS. A flood watch does not mean a flood is already occurring or will occur — it is meant to warn residents in the area that they should be prepared for one in case conditions get worse. Often, that means staying tuned in to local news and weather reports for any additional alerts and making sure you're ready to evacuate or seek shelter if necessary.
A flash flood watch offers a similar notice and means the conditions are right for a flood to happen quickly and suddenly. Ready.gov says it's important to stay alert if you're issued a flash flood watch, as you may need to seek higher ground with short notice. This is because a flash flood happens more quickly than regular flooding.
Flood warning vs. flash flood warning
If authorities have issued a flood warning in your area, it means a flood is imminent or occurring, says the NWS. If you are advised to evacuate when a flood warning has been put in place, you should take the orders seriously and do so as soon as possible, says Ready.gov.
Similar to a flood warning, a flash flood warning means a flash flood is expected or already happening. In this case, you should seek higher ground immediately, says Ready.gov.
Flash flood emergency: Rare but real
While rare, the NWS says a flash flood emergency alert means flooding conditions are so severe that they pose a major threat to life and can cause catastrophic damage. A flash flood emergency may be issued in cases where floodwaters have reached never-before-seen levels, multiple water rescue teams have been dispatched or when a major dam has failed.
Under a flash flood emergency, The Weather Channel says you should not travel unless you're told to evacuate or are already seeking higher ground away from a flooded area.
How to stay updated on flood conditions
A good way to prepare for any type of flood is to stay informed. The NWS shares official warnings, watches, forecasts and other information 24 hours a day on public radio and television broadcasts. You can also sign up to receive weather alerts on your smartphone by downloading the Federal Emergency Management Agency or American Red Cross applications.
Floods cause more damage than any other serious weather event, and the likelihood of experiencing one has increased over the past several decades, according to the U.S. Climate Resilience Toolkit. Since everyone is at risk for experiencing a flood, it's important to learn how to stay safe before a flood strikes so you can be better prepared.