A tropical air mass shifted into the area Tuesday, and for days, interacted with a stationary front to produce numerous rounds of storms. The storms had heavy rainfall rates of 1-3 inches per hour and repeated over the same locations in some areas.
Rainfall totals of 3-7 inches were reported across many areas from Tuesday night through Friday morning. However, there were some localized much higher amounts of 9-11 inches.
While 3-7 inches of rain can cause flooding, the unusual amount of rain that fell over the past month (2 to 3 times normal), created very wet soils and amplified the flooding. This water loading of the soils caused an unusually high number of mudslides. A high percentage of the rain that fell ran across the surface instead of soaking in, causing flooding on every river
in the area. Damage to infrastructure (such as roads and bridges), farm crops, homes, and businesses was also widespread.