Yellowstone Infrastructure Vulnerability

Summary of Results & Discussion
Results of this analysis show more assets in the study area are exposed to wildfires and earthquakes than any of the other evaluated hazards at YELL, largely due to the widespread nature of these hazards. This is likely to be the trend for these two hazards across the entire park. Flooding, stream channel migration/erosion, geothermal activity, and landslides are more spatially limited by proximity to the hazard source (e.g., rivers, geothermal basins, and steep slopes), and therefore affect fewer assets. Although there is widespread exposure to wildfires and earthquakes across the study area, some asset types have relatively low sensitivity to these hazards. For example, roads, trails, and parking lots are less likely to be significantly damaged by wildfires or earthquakes, when compared to buildings and bridges.

Using this protocol, flooding (riverine and surface runoff) is the most significant hazard in the study area of YELL in terms of total value. A significant portion of this value is from bridges, which are commonly built across water bodies, and inherently exposed to river-related hazards such as flooding. Therefore, the sensitivity of these bridges is extremely significant, as efforts to reduce sensitivity (e.g., proper sizing to accommodate storm event flows) are often the only way that vulnerability to flooding can be reduced for these assets. Finally, the study area selected coincides with some of the larger geothermal basins in the park, which can have complex hydrology. As a result, the flooding hazards in these areas includes surface runoff due to geothermal activity.

segments with high vulnerability using this protocol; worsening erosion or sudden shifts in the stream channel at any one of these hotspots (or near a bridge) could cause major access and traffic issues in this part of the park. It would benefit the park to monitor these segments, or conduct more detailed analyses, to determine if adaptation action is warranted.

Landslides are less significant in the YELL study area, as none of the evaluated point assets or trails have high vulnerability, and only 1% of the road length has high vulnerability. These results are a factor of the study area landscape, as only a few specific areas have steep-walled canyons or nearby slopes (e.g., Firehole and Gibbon canyons). Similar to stream channel migration/erosion, the road mileage with high vulnerability to landslides in the study area is relatively low. However, it is important to note again that even a small section of road damaged by landslides could cause major problems and delays.

Many assets in the study area of YELL are highly vulnerable to multiple natural hazards, several of which have significant value and/or priority to the park. These assets may provide a good starting point for developing adaptation strategies in this area of YELL. Only one building has high vulnerability to four hazards but has a relatively low value and priority to the park. Several buildings have high vulnerability to three of the evaluated hazards. The West Entrance to Madison Junction and Norris to Madison Junction road corridors have the most road segments with high vulnerability to three or more hazards. Along these corridors, there are several key segments/locations that have high vulnerability to a combination of earthquakes, flooding, stream channel migration/erosion, and landslides.

Each of the evaluated hazards is part of a dynamic natural system, which will certainly change over time. Some changes may be readily predictable, with the potential to increase or decrease asset vulnerability, while others may be more complex or interrelated. In addition, changing climate has the potential to amplify these changes, necessitating the periodic reevaluation of asset vulnerability at YELL as new data comes available.