The Meaning of the 100-Year Flood

3/1/2021 (Permalink)

Knowing some of the antiquated terminology surrounding storms can be important to understand how you need to prepare.

If you have never heard the term “100-year flood”, what was the first thing that came to mind? Most probably think that it is a great flood that happens every 100 years or a flood that lasts for years and years. What this term is actually used for is to describe a momentous flood. Because floods can vary in severity and cause, this is a term that is commonly used for those natural disasters that we see on the news. If it does not actually refer to a flood that occurs every 100 years, then how did this term come into play, and is how factual is a “100-year flood”?

According to the United States Geological Survey (USGS), this term came from the US government in the 1960s. To set a basis for the National Flood Insurance Program, they decided to use the 1-percent annual exceedance probability (AEP), which is “the probability of a flood event occurring in any year”. At this time, the government believed that it would be a fair balance between protecting citizens and overly rigid regulations. 

So, the next time you hear someone refer to the “100-year flood”, take peace in knowing that we will not be enduring a flood that lasts 100 years. It is, however, not a myth, and floods still occur, and they can be devastating. With the 1-percent probability (or 1 in 100), it could happen to you. If you find yourself in over your head (pun intended) with flooding and water damage, give us a call. SERVPRO of Northern Summit County can help you get your home or business restored in no time.