The dirty rain fell late Tuesday afternoon, the San Antonio Express-News reported. While the rain was welcome, residents were perplexed by and worried about its rust color.

Joe Baskin, a National Weather Service forecaster, said that the color was nothing to worry about. He said that smoke and ash had been carried from the fire near Mexico City.

"It's kind of unusual to have ash mixed in with rain," Baskin said. "It doesn't happen often. This stuff will push on through."

Any stains the rain caused on cars or windows should wash right off, Baskin said, and the ash was unlikely to cause any health problems.