Bureau of Economic Geology logo Texas Bureau of Economic Geology
Padre Island National Seashore: A Guide to the Geology, Natural Environments, and History of a Texas Barrier Island


A short field trip has been designed for Seashore visitors wishing to take a close look at various island environments found within the northern end of the National Seashore. By using the following road log and the accompanying map (fig. 111), visitors can guide themselves through the environments and observe them at their own pace. This drive, only a few miles long, affords a look at a complete cross section of barrier-island environments, ranging from Gulf beach to lagoon. The trip uses maintained roads and does not require a four-wheel-drive vehicle.

The following road log describes the various environments or points of interest that can be seen along a route beginning at the Seashore entrance on Park Road 22 and ending at the Laguna Madre shoreline in the Bird Island Basin area. Mileage, approximated to the nearest 0.1 mile, is shown both in cumulative miles and miles between observation points or convenient landmarks. The environments do not necessarily have to be seen in the order given in the road log; one can reverse the trip and recalculate the cumulative mileage. Although odometers of different vehicles vary, use of the map, which shows environments and observation points (fig. 111), should prevent confusion. Observation point numbers on the map correspond to those used in the road log.

Figure 111. Route for north Padre field trip. Observation points are described in the Road Log. (click on image for an enlargement in a new window)

For a more detailed description of the environments and the active processes affecting them, see sections on Environments of Padre Island and Laguna Madre and The Dynamic Barrier Island.


While this guidebook was in final preparation in August 1980, the eye of Hurricane Allen made landfall near Port Mansfield. One of the greatest hurricanes of the century, Hurricane Allen stalled and lost strength as it approached the Texas coast. Nevertheless, the hurricane's impact was severe along the National Seashore, where storm tidal surge heights were estimated at approximately 10 feet above mean sea level. All mapped washover channels (pl. I, in pocket) were activated by the storm tides.

The myriad effects of Hurricane Allen on Padre Island and its environments followed closely the scenario of previous hurricanes described in this guidebook (p. 38-41). The beach, fore-island dunes, and associated features were modified extensively in places by the storm as it moved across the National Seashore, eroding, transporting, and depositing the loose sediments that compose the island.

Normal day-to-day processes involving waves, currents, and winds will slowly reconstruct most of the features modified by the storm. Locally, however, some changes produced by Hurricane Allen will remain. These changes, of course, are to be expected and are part of the overall evolution of the dynamic barrier island.

<<< Previous <<< Contents >>> Next >>>

Last Updated: 28-Mar-2007