Grounded: An Enterprise-Wide Look at Department of the Air Force Installation Exposure to Natural Hazards
Aug 9, 2021
Recent natural disasters have underscored the vulnerability of Air Force installations to natural hazards. In 2018, Tyndall Air Force Base (AFB) experienced a direct hit from Hurricane Michael, causing $4 billion worth of damage. Flooding at Offutt AFB in 2019 damaged buildings, runways, and other assets. A wildfire near Vandenburg AFB delayed a scheduled rocket launch and endangered two space launch pads.
These incidents have prompted the Department of the Air Force (DAF) to examine how to improve AFB resilience to natural hazards. To reduce the exposure of these installations to the threat of disasters, the DAF asked RAND's Project AIR FORCE to assess base-level exposure to flooding, wildfires, and high winds and identify potential mitigation options. The analysis combined geospatial and other asset-level information with national hazard data for each base. The approach demonstrates how an enterprise-wide view of installation exposure to natural hazards can inform a variety of policy decisions.
Flooding can result from extreme weather or human factors, such as inadequate stormwater infrastructure. Climate projections suggest that the global intensity of storms will grow, as will the geographic distribution of severe storms. Flooding poses particular risks to some Air Force installations in coastal areas, which are subject to heavy rain and surges from hurricanes and tropical storms and to sea-level rise from climate change. The Special Flood Hazard Area (SFHA), as designated by the Federal Emergency Management Agency (FEMA), is an area with a 1-percent annual exceedance probability of flooding in any given year (usually referred to as a 100-year flood). Figure 1 shows the percentage of land in each AFB that is located in the SFHA.
As shown in Figure 1, two bases have more than 75 percent of their area in flood hazard zones: Langley (Virginia) and MacDill (Florida). More-granular analysis shows that Langley and MacDill each have multiple assets in flood hazard zones, including all runways. Wright-Patterson, Eielson, and Seymour Johnson AFBs also have assets in multiple categories in the SFHA zones.
Tyndall AFB suffered extensive damage from Hurricane Michael in 2018: Approximately 750 assets were hit. Future hurricanes could inflict even greater damage on high-risk bases (shown in Figure 2). To estimate the potential costs of future hurricane damage, the researchers simulated future building-repair costs for installations that suffer similar damage. The analysis simulated cases with roughly 15 percent higher (worst case) and 15 percent lower (best case) damage than the Tyndall case.
The simulation showed that five locations would have costs spanning a range similar to Tyndall's costs. Four locations, however (Lackland, Eglin, Robins, and Patrick), would have notably higher estimated costs. These costs stem from a combination of the number and types of buildings at these locations. The results suggest that the variation in assets exposed to a Michael-like hurricane could translate to substantially different repair costs for different installations.
|Base Name||Average estimated costs (billions of dollars)|
|Baseline Scenario||Best Case Scenario||Worst Case Scenario|
The average base-wide exposure to wildfire is low or very low for 80 percent of installations; however, 20 installations have areas with high or very high Wildfire Hazard Potential (WHP—see Figure 3). Vandenberg, Eglin, Beale, Mountain Home, and Moody AFBss have the highest relative average exposure. These five bases also have the highest percentage of base area with high or very high WHP. Fifteen other bases face elevated risks from wildfire exposure. Because fires threaten entire bases, an enterprise-wide look at wildfire risk needs to flag bases having even small areas with high exposure.
Even if wildfires do not directly affect areas on a base, they can affect critical infrastructure—such as electric power—on which DAF missions rely. The analysis also examined the exposure of key electric power assets outside the base in the surrounding region (Figure 3). Edwards AFB, for example, faces risks posed by wildfire exposure in areas outside the perimeter. Although the on-base exposure is relatively low, there are power lines nearby in the Los Angeles area mountains with high levels of exposure to wildfire.
|Mean wildfire potential on base|
|Mean wildfire potential for power line buffer||High||Patrick*, Keesler*, and Edwards* AFBs||NA||Mountain Home, Beale, and Moody AFBs|
|Moderate||Two unnamed bases*||Dyess*, Hill*, Charleston*, Robins, and Shaw AFBs, Hurlburt Field, and five unnamed AFBs, three of which have potentially disproportional risk from off-base threats||Ellsworth, McGuire, Tyndall, and Vandenberg AFBs|
|Low||9 unnamed AFBs, 4 of which have potentially disproportional risk from off-base threats||5 unnamed AFBs||Kirtland and Eglin AFBs|
|Very low||15 unnamed AFBs, 11 of which have potentially disproportional risk from off-base threats||2 unnamed AFBs||NA|
* Potentially disproportional risk from off-base threats
Many bases are exposed to more than one hazard. For example, Langley and MacDill AFBs have a large percentage of area exposed to current and future flooding from sea-level rise. Wright-Patterson has a high percentage of base area exposed to flooding and is also located in a high-wind zone. Moody AFB has about one-third of its base area in the flood hazard area, has a high base-level average wildfire hazard (relative to other bases), and is also exposed to relatively high winds.
The uneven exposure of installations to natural hazards and the presence of multiple hazards suggest that the DAF should look critically across the entire enterprise to improve installation resilience. However, although enterprise-level assessments of exposure can provide insights for the DAF, they do not replace deeper-dive, local assessments.
We recommend that the DAF take the following actions: