(WKBN) – Throughout the year we get flood warnings, flood advisories, and flood watches.

There are areal flood watches and warnings, river flood watches and warnings, and flash flood watches and warnings. These different watches and warnings can be confusing. You get even more confused as you read deeper into the terms within the watch or warning that may leave you scratching your head trying to understand what it all means.

Let’s walk through each warning and watch step by step to make sure you are prepared for these advisories throughout the year.

Is it a watch or a warning?

Ok, this needs to be addressed first. Remember, a watch means conditions are favorable for an event to take place. A warning means that there is an imminent threat of flooding.

Flood Advisories

According to the National Weather Service, a Flood Advisory is issued when flooding that is not considered a significant threat to life or property is expected or occurring. This usually deals with nuisance flooding problems, such as flooding in low-lying areas and areas of poor drainage, as well as minor flooding of streets and roadways. This type of flooding causes some inconvenience but is not generally considered a significant threat to life or property. Flood Advisories are normally issued as an Urban and Small Stream Flood Advisory. 

Flood and Flash Flood Watches

The National Weather Service issues Flash Flood Watches and Warnings. They are issued when the current and/or developing weather pattern is such that there is a potential for rapid flooding (also known as flash flooding), more widespread areal flooding, or river flooding according to the National Weather Service. The occurrence of flooding is neither certain nor imminent according to the NWS. 

Flood and Flash Flood Warnings

According to the National Weather Service, a Flood or Flash Flood Warning is issued to inform the public that flooding is imminent or in progress. It focuses on specific counties, communities, streams, or areas. Flash Flood Warnings are issued for flooding usually occurring within six hours of heavy rain. 

Areal Flood Warning

According to the National Weather Service, an Areal Flood Warning is issued for flooding that occurs more gradually, normally from prolonged and persistent moderate to heavy rainfall.  

An Areal Flood vs a Flash Flood

This is a confusing group of warnings and watches. They do mean different things according to the National Weather Service.

The National Weather Service states that a Flash Flood Warning is issued for flooding that normally occurs within six hours of heavy or intense rainfall. This results in small creeks and streams quickly rising out of their banks. Dangerous flooding in areas near these creeks and streams, as well as low-lying flood-prone areas, develops very quickly and is a significant threat to life and/or property.

According to the National Weather Service, an Areal Flood Warning is normally issued for flooding that develops more gradually, usually from prolonged and persistent moderate to heavy rainfall. This results in a gradual ponding or buildup of water in low-lying, flood-prone areas, as well as small creeks and streams. Flooding normally occurs more than six hours after the rainfall begins, and may cover a large area. However, even though this type of flooding develops more slowly than flash flooding, it can still be a threat to life and property according to the NWS.

River Flood Warning

According to the National Weather Service, a River Flood Warning is issued when a river is forecast to go above its designated flood stage at the forecast point.

River Flood Warning Terms

Bankfull Stage
According to the National weather service, the bankfull stage is an established gage height at a given location along a river or stream, above which a rise in water surface will cause the river or stream to overflow the lowest natural stream bank somewhere in the corresponding reach. The term “lowest bank” is, however, not intended to apply to an unusually low place or a break in the natural bank through which the water inundates a small area. Bankfull stages on streams with natural or manmade high banks can be defined by the predominant vegetation line on the banks. The bankfull stage on many streams is associated with the two-year recurrence interval flood. Bankfull stage is not necessarily the same as flood stage.

Action Stage
The National Weather Service states that the Action Stage is the stage which, when reached by a rising stream, represents the level where the NWS or a partner/user needs to take some type of mitigation action in preparation for possible significant hydrologic activity. The type of action taken varies for each gage location. Gage data should be closely monitored by any affected people if the stage is above action stage.

Flood Stage
Definition from the National Weather Service
An established gage height for a given location above which a rise in water surface level begins to create a hazard to lives, property, or commerce. The issuance of flood (or in some cases flash flood) warnings is linked to flood stage. Not necessarily the same as bankfull stage.