A "100-year flood" means a 1% chance of that level of flooding happening each year. Houston saw three 500-year flood events within three years from 2015 to 2017, including Hurricane Harvey.

Central Texas faced historic, catastrophic flooding this month, with some meteorologists calling these floods 1000-year ...

The term "100-year flood" is often misunderstood—many believe it means a flood that happens once every 100 years, but that’s not how probability works. Instead, it refers to a flood that has a ...

A 500-year flood means such an event has a 1 in 500 chance, or 0.2 percent, of occurring in a year. Another concept scientists use is how frequently an event of a certain intensity is expected.

A 500-year flood means such an event has a 1 in 500 chance, or 0.2%, of occurring in a year. Another concept scientists use is how frequently an event of a certain intensity is expected.

And if you expand that to a 30-year period, a life of most mortgages, it's a 26% chance that you will see water in that 100-year flood plain, or 1% chance area over the span of 30 years." ...

OREM, Utah (KSTU) - The city of Orem, Utah, is calling this week’s heavy rain a “100-year flood event.” Cleanup woes continue for the families who had water break through into their homes.

This is what forecasters mean when they talk about a 100-year flood. AP FILE - Cars are submerged on a freeway flooded in the aftermath of Hurricane Harvey near downtown Houston.