Sometimes a weather event comes along that is Complete Series Archivesso extreme it exceeds the ability of weather forecasters to accurately represent it on a map. That is the case with Hurricane Harvey, which weakened to a tropical storm on Saturday and dumped so much rain on southeastern Texas that the National Weather Service's (NWS) maps needed to be altered.

With more than 30 inches of rain falling in just a few days, the NWS added a lavender layer to its rainfall map to indicate areas that have already seen what it has called "unfathomable" amounts of rain.

This Tweet is currently unavailable. It might be loading or has been removed.

With 15 to 25 more inches expected in the Houston and Galveston areas, catastrophic flooding is expected to continue, the agency warned on Monday, with eventual rainfall totals potentially reaching 50 inches in some locations.

If this number is reached, it would set a statewide record, and would also be the heaviest rain to result from a landfalling tropical storm or hurricane on record in U.S. history.

On August 27 alone, Houston received 16.07 inches of rain, making it the wettest day in the city's history. August is already its wettest month on record, as well.

The need for a new color on the weather map is reminiscent of what occurred in Australia during a scorching heat wave in the summer of 2013.