Mapping Physical Risk and Social Vulnerability to Hydrologic Hazards in the Intermountain West

The increasing prevalence of hydrologic hazards as the climate changes creates a pressing need to identify and assess which areas and communities will be most at risk if these hazards do occur. While there has been research into what areas will be most at risk for specific hazards (e.g., floods, droughts, or wildfires) there is limited research that looks at multiple hazards together along with social vulnerability and environmental justice impacts. I focused this work in the Intermountain West, which represents an interconnected regional system that faces a similar set of water-related challenges. For this project, I used QGIS to explore data from FEMAs National Risk Index and the EPA’s Environmental Justice Screening and Mapping Tool. Using these datasets, I identified where drought, wildfire, flooding, landslides, and heatwaves are likely to coincide and which communities in this region will most likely experience the highest risk from these hazards. I also identified the areas that are at higher risk in multiple categories and the most at risk counties in each state using Excel to analyze the numerical data. I did this by normalizing the data and finding the counties in the top twenty percent for each variable. Some variables are related to social and economic data such as the percent of residents who are low income, younger than 5, or older than 64. Other variables are related to the hazards themselves like the number of instances of a certain event taking place, the total expected annual loss due to said events, and the area exposed to the hazard. Results show that the included areas of California are the most at risk from physical hazards overall while Wyoming is the least, and in terms of environmental justice and social vulnerability New Mexico is at higher risk compared to other states being looked at for both metrics. This work is meaningful because co-occurring hazards can be especially damaging and some things might be missed when only looking at individual hazards.