SOUTH MISSISSIPPI FLOODS OF APRIL 1955 Prepared by the U.S. Geological Survey in cooperation with the Mississippi Geological Survey and the Mississippi State Highway Department February 1956 Open File Release No. 4 TABLE OF CONTENTS Introduction General description of storm and floods Stream-gaging stations Partial-record sites Miscellaneous measurement sites Summary of flood stages and discharges Flood damages PLATES I Flooded farm house south of Columbia II Flooded barn near State Highway 13 south of Columbia III Ponded area in vicinity of Hattiesburg IV Flooded farm house at Rawls Springs near Hattiesburg V Silver Creek bridge in Foxworth VI Signal light destroyed by Silver Creek at Gulf-Mobile & Ohio Railroad crossing of the main street in Foxworth VII Homochitto River at U.S. Highways 61 and 65 near Doloroso VIII Car in flooded drainage ditch on Santa Clair Street in Jackson FIGURES 1. Map of South Mississippi showing sites for which data are presented 2. Map of South Mississippi showing isohyetal lines for rain of April 12, 13, 1955 3. Comparison of South Mississippi rain of April 12, 13, 1955, with frequency curves 4. Accumulated rain at selected South Mississippi stations 5. 24-hour rainfall frequency curve - South Mississippi 6. Strong River at D'Lo, flood frequency (1929-55) 7. Flood hydrographs, South Mississippi streams 8. Relation of unit discharge to size of drainage area TABLES 1. Maximum rainfall rates, April 12, 13, 1955 2. Rainfall in South Mississippi, April 9-14, 1955 3. Summary of flood discharges in South Mississippi for the flood of April 1955 ABSTRACT Heavy thunderstorms on the afternoon and night of April 12, 1955, caused extremely high floods on many small area streams in southern Mississippi. The rains were general over the entire area, but there were many centers of torrential rainfall. Unfortunately, recording gages were not located in the areas of most intense precipitation. The extremes of precipitation, 10.14 inches at Merrill and 1.27 inches at White Sand which are only 55 miles apart, indicate that the concentrated centers of rainfall did not cover large areas. The highest intensity at a recording gage was at Tylertown where 3.63 inches fell in one hour and where a total of only 6.10 inches fell in 16 hours. Comparison of the intensity and magnitude of this rain with frequencies computed by Yarnell(1) indicates a recurrence interval of at least 50 years for the shorter periods of time; therefore, it can be reasonably assumed that the rainfall intensity as well as the magnitude in the vicinity of Merrill (10.14 inches) and Columbia (9.23 inches) was even more infrequent. The intensity of the rain in concentrated areas caused extreme floods on small streams but only medium high stages on the larger streams. Although there is very little factual data on small areas for past floods in southern Mississippi, rainfall comparison indi- cates that the highest data presented herein are probably among the greatest known. During the flood period, floodwaters covered many highways and city streets. State Highway 26 between Lucedale and Wiggins and U.S. Highway 98 between Hattiesburg and Columbia were closed temporarily during the height of the flood. The City of Columbia had water 3 feet deep along its main street, and Foxworth was covered by more than a foot of water from Silver Creek. Many people residing in low-lying areas had to evacuate their homes as the floodwaters rushed in. In Beat Two, Forrest County, one bridge was destroyed, ten others damaged, and an estimated 10,000 yards of gravel was washed from the roads. At least two persons drowned. This report presents flood data for gaging stations, flood runoff from very small watersheds, rainfall data, and other related material. Its primary intent is for the design of small drainage structures in southern Mississippi. It has been prepared as part of the cooperative program on surface water investigations between the U.S. Geological Survey and the Mississippi Geological Survey and the State Highway Department. (1) Yarnell, David L., Rainfall Intensity-Frequency Data LizardTech's Djvu plug-in is needed to view these reports. CLICK HERE TO VIEW THE ENTIRE REPORT For questions or comments, contact K. Van Wilson.