Hurricane Alicia Storm Surges and Shore Processes

Hurricane Alicia moved inland over the Texas coast during the night of August 17, 1983 creating waves and surges in the Gulf of Mexico and adjacent bays. Waves eroded beaches and dunes and surges overtopped low-lying areas of barrier islands and inland areas adjacent to the bays behind the barriers. A three-day survey of field evidence of water levels and flow directions was carried out one week after the storm. Physical evidence, such as the elevation of debris lines, water marks in buildings and debris caught on fences was used along with additional data from tide gages operating in the area to estimate the maximum flood levels and flow directions associated with the storm. Before and after aerial photography was used to obtain data on beach recession, retreat of the vegetation line behind the beach and extent of oyerwash deposits. The evidence gathered shows that the barrier islands were overtopped from front-to-back in some areas and from back-to-front in other areas with quite different results. There was little or no beach erosion to the left of the storm as it came ashore; however, serious beach erosion occurred for 18 miles (29.0 km) to the right of the storm and there was significant erosion for 55 miles (88.5 km) to the right of the storm. Maximum water levels in the Gulf, including the effects of normal tides and storm effects, were 9 to 11 feet (2.74 to 3.35 m) and maximum water levels along the nothern portion of Galveston Bay were 11 to 14 feet (3.35 to 4.27 m).