EFFECTS OF HURRICANES RITA (2005) AND IKE (2008) ON COASTAL FEATURES IN SOUTHEASTERN TEXAS AND SOUTHWESTERN LOUISIANA

Hurricane Rita (2005) and Hurricane Ike (2008) had similar devastating effects on the southwestern Louisiana and southeastern Texas coasts. Rita's landfall, just east of the Texas-Louisiana state line, and Ike's landfall, in the east end of Galveston, TX, was 110 km apart. Rita was a medium Saffir-Simpson category 3 hurricane (193 kph sustained wind at landfall); Ike was a very strong category 2 hurricane (177 kph sustained wind at landfall), but Ike was a larger storm in geographic area, and produced storm surges over a much larger area that Rita. Both pushed Gulf of Mexico salt water more than 50 km inland over a broad front.

Rita's highest recorded storm surge was 4.5 m at Constance Beach, LA, and it was 4 m at Calcasieu Pass, La, but Ike had a 3.6 m surge at Calcasieu Pass, with a center 110 km farther west! Devastation in southwestern Louisiana was comparable to Rita, because of an almost equal storm surge of longer duration, without the hurricane-force winds of Rita.

Ike's storm surge, as high as 5.5 m, completely over washed the Bolivar Peninsula, TX, which has a maximum elevation of ~3.7 m, resulting in massive damage to property and loss of lives. Beach erosion was widespread and all dunes were destroyed, dune sand washed to the middle of the peninsula. The worst damage was at the town of Gilchrist, where all except one of 200+ homes were completely destroyed. Damage was accentuated by a Geotube installed to “protect” the town. Instead, it caused deepening of water by erosion of sand seaward of the tube during rising storm surge, forcing the waves to break on the tube as storm surge topped it, putting beach houses in the plunge pool behind it. Return flow during the falling storm surge was channeled through gaps in the partially destroyed tube, causing deep gullying, which removed the remains of concrete slabs. In areas east of Gilchrist and High Island, where there was no tube or houses, the rising surge built a storm beach of shells up to 3 m above normal sea level, and the return flow cut shallow gullies and deposited multi-lobed, finer sand deposits in shallow water just seaward of the beach. These sand lobes are being reworked by fair-weather waves. Part of the McFadden beach area east of High Island with little sand, which was transported into the marsh, was left with dissected, compacted marsh muds forming the beach. This mud beach is gradually being covered by sand brought by the westerly longshore current.