Explaining Flash Flood Emergencies
Flash flood emergency warnings are dire alerts issued by the National Weather Service in high-impact situations that warn potentially destructive and life-threatening flooding is imminent or ongoing.
1. It's The Highest Level Of Flood Alert
- Flash flood warnings are common:The NWS issues these by the thousands each year. Typically,at least some streets and roads will be flooded in areas covered by a flash flood warning,which can be dangerous for motorists. Some of these warnings cover events in which a few low-lying properties have taken on some water.
- Flash flood emergency warnings are rare: Given the large number of flash flood warnings issued,just over 20 years ago the NWS begun issuing a more extreme alert,called a flash flood emergency,to highlight rare occasions when there is a major threat to life or potential for catastrophic damage.
- When issued,these flash flood emergencies are embedded within existing flash flood warnings as a headline near the top of the warning. They can cover parts of one or more counties,like the example below from West Virginia in February 2025.
2. The Triggers For A Flash Flood Emergency
According to NWS guidelines,situations that may trigger a flash flood emergency include:
- A local or state emergency manager has confirmed that rapidly rising water is placing,or will place,people in a life-threatening situation.
- Water is expected,or has already rapidly risen,to levels where people in typically safe locations during other flash flood events will be in danger. These include cases where water could encroach several feet above floor level in a home,requiring rescue and putting the entire home at risk.
- Several swift-water rescue teams have been deployed to a flash flood of unusual magnitude.
- River and stream gauges indicate water has risen to at least major or rarely seen flood levels.
- The complete failure of a large,high-hazard dam would have a catastrophic impact on downstream areas.
This is a similar concept to,which are issued in cases where catastrophic damage and a severe threat to life is imminent or ongoing with a confirmed tornado.
3. Actions You Should Take If One Is Issued
This highest flash flood alert will trigger your smartphone to screech loudly,known as a wireless emergency alert.
If you're in a flash flood emergency:
- Move to higher ground immediately.
- Do not travel unless you're either escaping a flooded area or are ordered to evacuate by local officials.
- Otherwise,avoid walking or driving through any flood water. You may not be able to tell how deep the water is and the road underneath could have been washed out. Even slow-moving water can knock you off your feet or float your vehicle,sweeping you away downstream.
4. They Are A Rare,Small Percentage Of All Warnings
According to the Iowa Environmental Mesonet,only 29 flash flood emergencies were issued across the country in 2023,comprising less than 1 percent of all NWS flash flood alerts.
2024 had a much higher number of emergency warnings,largely because of Hurricane Helene's flooding in the Southern Appalachians. Out of just over 90 flash flood emergencies issued in 2024,34 of them were because of Helene's catastrophic flooding.
Even with that,the number of flash flood emergencies issued in 2024 was just 2% of the total number of NWS flood alerts,which topped just over 4,400.
(MORE:Most Shocking Things From Helene's Final Report)
