Helene Vs Historical: Exploring how Hurricane Helene Compared to Other Hurricanes and the Probable Maximum Precipitation
Virginia Dam Safety requires that high hazard dams are designed to contain inflow from the Probable Maximum Precipitation (PMP). This presentation aims to emphasize the importance of this design criterion by examining historical hurricane impacts, the potential exacerbation of these impacts by pre-existing saturated soils, and the effectiveness of emergency response plans. Hurricanes have historically impacted Western and Southwestern Virginia, with notable events including Hurricane Camille in 1969, Hurricane Isabel in 2003, Hurricane Michael in 2018, and Hurricane Helene in 2024. These events have provided valuable data on rainfall, flooding, and dam safety. For instance, Hurricane Camille brought record rainfall, leading to severe flooding and loss of life throughout the region. Similarly, Hurricanes Isabel and Michael caused significant damage, highlighting the region's vulnerability to such extreme weather events. The impacts of Hurricane Helene on Western North Carolina and Southwestern Virginia serve as a critical case study. The recent effects of the hurricane on mountainous locations such as Asheville, NC and Radford, VA demonstrate why utilizing the PMP in design standards is appropriate for high hazard dams. Before and after photos, maps, and USGS gage data will illustrate the extent of the flooding and damage. To further emphasize the importance of utilizing the PMP to develop design standards for high hazard dams, simulations will transpose the rainfall from Hurricane Helene onto the drainage areas for several dams in Southwestern Virginia including:
- Claytor Lake
- Smith Mountain Lake
- Carvin Cove
Author Bio
Kyle Jacobs is a graduate of Virginia Tech with BS and MS degrees in Biological Systems Engineering. He is a water resources design engineer with 5 years of experience with Freese and Nichols in the Alexandria, VA office. His primary responsibilities are in hydrologic and hydraulic modeling and analysis, Emergency Action Planning, NRCS assessments, planning, and spillway design for dam rehabilitation projects.
