Assessing lightning risk in vulnerable outdoor environments

Despite large improvements in lightning detection technology and safety awareness in recent years, lightning continues to cause injuries and fatalities throughout the United States. Many fatalities occur as a result of individuals enjoying outdoor leisure activities. The analysis and assessment of lightning risk allows for the quantification of lightning danger surrounding any particular event and is therefore advantageous for the continued advancement of lightning protection. While lightning risk analyses are often designed for application to structures and produce an annual value of risk, the framework of such an analysis can be adapted to apply to humans and for shorter time durations. This research creates a risk analysis and assessment method to quantify lightning risk with respect to human safety. Risk is calculated for selected cases that represent scenarios particularly prone to contributing to lightning fatalities. The analysis incorporates the use of real-time total lightning data from chosen thunderstorms to be able to quantify risk over shorter time scales (1 hour, 30 minutes, 10 minutes, and 1 minute) as well as illustrate evolving risk. Also unique to other risk analyses is the incorporation of distance dependencies similar to those used in "range-ring" lightning safety studies. Risk output is compared with two varying tolerability frameworks to draw conclusions about potential dangers associated with each case. The risk analysis and assessment performs well in quantifying the hazard and exposure associated with each lightning risk scenario. Activities associated with large collection areas or chosen storms with high flash densities led to particularly large risk magnitudes. When the analysis was applied to two true fatality cases, it was found that risk decreased at the time of each fatality. Risk magnitudes often fell in a region of tolerability that bordered both tolerable risk and unacceptable risk. Overall, the risk analysis and assessment provides an effective underlying framework to quantify the lightning hazard with respect to human safety for outdoor lightning risk scenarios, and could be expanded upon in the future to quantify more characteristics human vulnerability.