It rained so much in Houston that NWS added new colors to rainfall maps

When you have 30 or more inches of rain falling over only a few days, adjustments have to be made. The National Weather Service is no exception.

The weather forecasters have had to add new colors to their weather maps, Mashable reported.

Explore>>Tropical Storm Harvey: 12 trillion gallons of rain have hit Texas, experts say

NWS added a light purple, or lavender, layer to show what it is calling "unfathomable rain," or greater than 30 inches.

And more rain is on the way.

Explore>>Hurricane Harvey: How can you help 

This isn't the first time a new color was needed to illustrate a weather phenomenon. In 2013, Australia needed another color for a deadly heat wave that blanketed the island continent, the Guardian reported.

Explore>> Read more trending news

Experts say 12 trillion gallons of rain has fallen in Texas during Harvey.

Explore>>Houston braces for more flooding after Harvey: Live updates