Transcript:
When a flood hits, you might hear the news describe it as a 100-year flood.
But as the climate changes, this term may not be as accurate as it once was.
A ‘100-year flood’ refers to a flood with a 1% chance of occurring each year – meaning, on average, a flood that bad will happen once in 100 years.
The same goes for 500-year or 1,000-year floods.
These likelihoods are calculated using historical records.
But as climate change brings extreme weather and raises sea levels in many areas, the likelihood of a serious flood could be higher than these terms imply.
Moftakhari: “The 100-year events that have been calculated based on historic records, let’s say back in 1950s or ‘60s, are no longer 100-year events.”
Hamed Moftakhari is an engineer at the University of Alabama.
His research has found that by the end of the century, many coastal areas could see 100-year floods about once a year, because of rising sea levels.
Moftakhari: “We are going to experience that destructive water level much more frequently.”
So it’s important for people who hear these terms to understand that the likelihood of serious floods might be higher than the language implies.
This article first appeared on Yale Climate Connections and is republished here under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.