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.

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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.

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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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