The past few years have been the years of flood across parts of Louisiana. The system that moved through Saturday night and Sunday followed the same path as many of its predecessors.
The hardest hit areas were Evangeline parish and the southwestern areas of Avoyelles parish.
Looking back at past radar, it appears the area received four separate bouts of very heavy rainfall. Rainfall that eventually led to widespread flooding.
The first large storm moved across Allen, Evangeline, Rapides, and Avoyelles between 7:30-9:30pm. This was the same storm that produced golf-ball sized hail in parts of Allen parish. This storm also dumped the first round of heavy rainfall across Evangeline, southeastern Rapides, and southwestern Avoyelles parish.
Second line of storms developed between 12:30-1:30am, moving across the same area. This storm was also severe-warned, producing gusty winds and very high rainfall rates. Lines of storms continued to re-develop over the same areas, keeping rainfall rates of 2-3 inches per hour over the area from 2am through about 6:30am.
Once the rain stopped, radar estimates showed that a swath of 6-11 inches of rain had fallen. Looking at ground truth from some weather watchers in the area, the radar estimates appear to be pretty accurate. Evangeline parish, just north of Eunice, saw 6-8 inches of rain within a 3-hour period, while the wider area of Evangeline through southwestern Avoyelles received 8-11 inches of rain within a 6-hour period. Point Precipitation Frequency Estimates show that areas that received the highest rainfall totals (close to 11 inches) in this event saw a 1 in 200 year flood. This means that a flood like this, statistically, only happens about once every 200 years. Other areas, however, saw closer to a 1 in 100 year flood. Problem with that is the fact that we have had about 4-5 of these types of floods within the past few years. If the law of averages is correct and everything must balance out, hundreds of years of less or no flooding must be coming! Let's hope so!