DALLAS (AP) — Decades of additional weather data have led federal officials to reconsider rainfall totals in Texas that define 100-year weather events and caution that extreme rainstorms will strike the state more frequently.

The National Oceanic and Atmospheric Administration on Thursday released a study finding that in the Houston area, for instance, 100-year estimates increased from 13 inches to 18 inches for a 24-hour period.

Rainfall previously classified as 100-year events are now more frequent 25-year events.

A 100-year storm is one that on average occurs every 100 years, or has a 1 percent chance of happening in any given year.

Earlier rainfall estimates provided by NOAA were based on data that in some cases are more than 50 years old.

The findings have wide-ranging implications, including emergency officials rethinking flood risks and new engineering standards for development.

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