"The main reason was the South Fork Fire last year that burned directly west of Ruidoso," Grzywacz said. "The soil wasn't able to absorb any of the rainfall, and it runs right down into Ruidoso. Normally, if you had that vegetation still there, it could absorb it. For the Ruidoso monsoon season, it was above average rain but not record rainfall."

Watch the terrifying moment a New Mexico home was swept away in raging floodwaters on July 8. Several people died in the storm.

More than 300 flooding reports have occurred across the U.S. since last Friday, with more heavy rain expected from Texas to the Mid-Atlantic.