Quarterdeck Volume 5, Number 1, Spring 1997
Tropical Storm Josephine damages Texas beaches
Mead A. Allison
Beach communities along the upper Texas coast are feeling particularly vulnerable these days in the wake of damage inflicted by Tropical Storm Josephine last October. The storm eroded up to 20 meters of shorefront property on Galveston Island and the Bolivar Peninsula-the worst damage to the area since Hurricane Alicia in 1983. Several houses were lost at Caplen Beach on Bolivar Peninsula, and "first row" houses in many other communities now sit perilously close to destruction.
Additional damage occurred in a minor high water event in November along beaches left without dune protection by the storm. The beach loss caused a flurry of stop-gap measures by coastal communities. Galveston County provided large bales of hay which have been transported to the beach, placed behind sand fencing, and covered with sand trucked in from elsewhere.
Tropical Storm Josephine formed off the coast of Tampico, Mexico on October 4th, 1996 and tracked across the Gulf of Mexico toward the Florida Panhandle, where it made landfall on the night of October 7th. During most of its passage across the gulf, maximum storm winds reached only about 56 km/hr (35 mph), increasing to 113 km/hr (70 mph) shortly before making landfall. How did this minor tropical system, that was more than 482 kilometers (300 mi.) away at its closest point on October 6th, do so much damage to the upper Texas coast?
The answer comes from wind and wave measurements from the National Oceanic and Atmospheric Association's Buoy 42035, located 40 kilometers (25 mi.) east of Galveston Island in 15.8 meters (51 ft.) of water. Although peak winds on the morning of the 6th reached only 15 m/sec (34 mph) at the buoy, winds blew above 10 m/sec (22 mph) for over 100 hours. This sustained period of high winds generated hourly average wave heights up to 3.5 meters (11 ft.).
Equally important, the winds were northeasterly. Due to the rotation of the earth and the orientation of the upper Texas coast, northeasterly winds caused water to pile up at the shoreline. The accumulation was recorded by a tide gauge on the Galveston Pleasure Pier on the seawall operated by the Texas Coastal Ocean Observation Network (TCOON). Water levels climbed to 80 centimeters above the normal 30 to 40 centimeter tidal range on October 6th and 7th. It was the highest level recorded by this gauge since it began service in May 1992.
Tide gauges from Sabine Pass to South Padre Island recorded similar water levels. This combination of high water and large waves for a sustained period generated the severe beach erosion on Galveston Island and Bolivar Peninsula.
The lesson we learned from Tropical Storm Josephine is that Texas shoreline communities can suffer damage from more than just direct hits by major hurricanes. The October-November erosion event parallels the effects of major winter storms on barrier islands of the Atlantic coast. Along the North Carolina Outer Banks, for instance, the most severe erosion in recent times was not caused by a hurricane, but by the Ash Wednesday Storm of 1962. This so-called "nor'easter" blew for over three days with a wind direction and shoreline orientation similar to Tropical Storm Josephine in Texas.
The most sobering thought Josephine evokes is that this level of damage was caused by water levels only about 80 centimeters (3 ft.) above normal. Major hurricanes such as the 1900 and 1915 storms that struck Galveston Island brought storm surges of over five meters (17 ft.) above normal.
The October-November erosion event should serve as a wakeup call to Texas homeowners building in these extremely vulnerable areas.
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Last updated June 7, 1997