![]() ![]() This highlights the vulnerability of populations in Texas to flood-related dangers. Population-normalized annual flood-related death rates show a steady decline however, from 1959 to 2008, Texas was the only state to record a flood-related fatality in each year ( Sharif et al. In these events, over 50% of the fatalities are associated with flash floods, and 77% of these are motor vehicle related. Floods in Texas are characterized by frequent events that result in less than 20 deaths per occurrence with large individual events yielding more fatalities. 2000 Ashley and Ashley 2008 Sharif et al. It has been well established that more fatalities and injuries due to flooding have occurred in Texas than any other state in the contiguous United States (CONUS) (e.g., Smith et al. This underscores the danger that floods, especially flash floods, still pose to people across the United States. Compared to other weather-related threats over this time period, only flood-related fatalities failed to decrease even with the number of flood events per year staying relatively constant. The study also did not find any significant decrease in flood-related fatalities or risk over the 47-yr period, despite modern advancements in communication and flood mitigation. 1996).ĭuring the time period from 1959 to 2005, Ashley and Ashley (2008) found that 4586 flood-related fatalities occurred in the continental United States with the most deadly events being flash flood or tropical cyclone related. The forecasting of floods is a complicated interplay between hydrologic and meteorological forcing, where not only the occurrence of an event, but also the magnitude is essential to evaluate potential impacts (e.g., Doswell et al. Furthermore, storm motion characteristics play a central role in influencing the rainfall accumulation totals. The local- and large-scale topography, regional land use, and preceding soil moisture characteristics all play an important role in the evolution of flooding scenarios (e.g., Funk 2006 Collier 2007). The occurrence of floods and flash floods in any particular region are not solely dependent upon the rainfall amount or rate. In many parts of the world, including the United States, flooding continues to pose a serious threat to human life, property, and infrastructure. These results show that the overall atmospheric conditions are much more important for determining the intensity and occurrence of extreme rainfall in central Texas than the local topography, but the Balcones Escarpment can cause subtle hydrologically important changes in the location of the maximum accumulation. However, the location of the maximum precipitation was slightly, but consistently, shifted to the north and west. ![]() The removal of the Balcones Escarpment did not change the overall characteristics of any of the three rainfall events, with the spatial pattern and magnitude of precipitation similar between the control and terrain-modified simulations. Then, the Balcones Escarpment was removed by moving the associated terrain gradient to the north and west. Numerical simulations for each event were run at convection-allowing grid spacing using the Weather Research and Forecasting (WRF) Model and were used as control runs. The purpose of this study is to evaluate the effect of the Balcones Escarpment in three cases of extreme precipitation in which the rainfall was maximized near the escarpment. While the hydrologic effects of the Balcones Escarpment are well known, the meteorological impacts are uncertain. Urban centers such as San Antonio and Austin, Texas, are located along this terrain feature and have suffered at times, even with mitigation strategies, catastrophic flood damage. Specifically, the Balcones Escarpment, located in central Texas, creates extremely favorable hydrologic characteristics for damaging floods. The proximity to the Gulf of Mexico and local topography makes central Texas particularly prone to heavy precipitation and deadly flood events. ![]()
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