What is an Areal Flood Warning?

Maybe you heard about an areal flood warning issued by a weather news service, but are unsure what it means?

An areal flood is a new term that was adopted by the National Weather Service a few years ago. This became necessary to distinguish it from a flash flood.

An areal flood warning is issued when flooding is expected to build up gradually in a specific geographic area, potentially a large area. [1]

Learn more about what meteorologists mean by an areal flood and what to do if an areal flood warning is issued below. In this article, I explain all you need to know about this new term.

What Does Areal Literally Mean?

‘Areal’ is an adjective of the noun ‘area’. The Free Dictionary [2] defines it as “of or relating to or involving an area”. This is the literal means of the word ariel.

Areal Flooding is Distinguished from Flash Flooding

Unlike flash flooding in which there is a quick burst of rain, the rain during areal flooding is more gradual. It is sustained over a longer time period. Areal flooding conditions develop as a result of prolonged rainfall that eventually leads to more persistent and heavy rainfall. In flood-prone areas, areal flooding results in a gradual accumulation of water and ponding.

Areal flooding usually occurs some hours after the initial onset of rain, normally six or more. In comparison, a flash flood is a much more sudden outburst and can even take a mere few minutes to become a violent flood (or within six hours). Also, the flooding in an areal flood is usually over a large area, hence the term. A flash flood is normally more localized than area-wide.

An areal flood is also distinguishable from a flood that occurs due to a large body of water without involving rain.

When an Areal Flood Warning is Issued

Areal flooding is no less severe and dangerous than flash flooding, but as long as you know the conditions are of an areal flood and not ordinary rainfall, you may have more time to prepare. If an areal flood warning is issued, treat it seriously and make all the preparations necessary as you would for a flash flood warning. All floods are a potential threat to life and property.

Although this article was focused on explaining what an areal flood warning is, i.e., a gradual area-wide flooding, here is a quick reminder of some things you can do to remain safe when such a warning is issued.

If you are indoors:

  • A flood warning, whether of an areal flood or flash flood, is still a flood warning, so treat it just the same and take all necessary precautions as you would for any flood.
  • Stay away from basements, tunnels, sewers, etc.
  • Make arrangements to move your family, essential belongings, and valuables to higher ground.

If you are outdoors:

  • Don’t attempt to cross low-water crossings or covered bridges.
  • Never attempt to cross a flowing stream of water, even on foot. A person can be easily swept off their feet by only six inches of rapidly flowing water. Only walk in water if necessary, if the water is not flowing rapidly.
  • Don’t remain in an automobile unless you are certain you can follow a safe escape route. Still, be wary of all puddles unless you know the roads and potholes. A car can easily lose control with only one foot of rapidly flowing water.

Here is a YouTube video by CBS19 that explains different flood alerts, including areal flood warnings.

Take a look at some of our related articles below.


[1] WTRF. West Virginia and Ohio areas under areal flood watch. Retrieved from https://www.wtrf.com/weather/west-virginia-and-ohio-areas-under-areal-flood-watch/. WTRF. 2022.

[2] AREAL Definition – https://www.thefreedictionary.com/areal

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