Along the West Coast, destructive megafires are becoming more common, with similarly disastrous effects on highways. Labor Day, September 7, 2020 – began with scorching, dry, hurricane-force easterly winds that fueled flames in WA, OR, and CA, igniting megafires that broke previous wildfire records. The current study represents the first empirical effort to assess the impact of megafires and their subsequent destruction of highways that can advance theoretical and practical knowledge of meg afires and their destructive capacity to highway infrastructure.
To determine why highway infrastructure damage from megafires is increasing we looked at the history of megafires in the three western coastal states in the US and the relationship to highway damage caused by them. megafires were documented in OR and CA during the 19th century and not surprisingly without any highway damage being noted, probably because few highways had been established by that time. The reasoning behind this lack of documentation during the 20th century includes a) the roadway networks were only beginning to be built, b) each state's Department of Transportation (DOT) was just beginning to be established (WA in 1905, OR in 1913, and CA in 1910), and c) federal government agencies were established only by the second half of the 20th century: the US Department of Commerce was established in 1903, but only became the Government's principal transportation agency in 1950, while the Federal Highway Administration (FHA) was established in 1967 and the Federal Emergency Management Agency (FEMA) debuted in 1979. Before the 2020 Labor Day wildfires, WSDOT had only submitted one request to the FHA for financial reimbursement due to highway damage from wildfires in 2014, while ODOT had only submitted two requests to the FHA for financial reimbursement due to highway damage in 2015. Caltrans representatives expressed uncertainty regarding when the office started requesting financial reimbursement from FHA but indicated that they started keeping track sometime in the 21st century. While Caltrans has not specifically captured roadway damage directly as it relates to wildfires, a recent research project developed by UC Davis was created to assist Caltrans in its efforts to do a wildfire susceptibility risk assessment for fuel reduction in their right-of-way alongside their highways. Their findings support the evaluation of infrastructure risk, which can be utilized to rank places for treatment, provide a method for monitoring regions that have been treated and have had their risk reduced over time, and involve local governments and wildfire fighting units in the coordination of landscape fire risk reductions[45].
Plausible factors that influence roadway damage from megafires are the result of a century of fire exclusion policies, increased fuel loading, the lengthening of the 'fire' season—the annual period during which vegetation fuels are susceptible to combustion—increased tree mortality and shifting topography/terrain. While these large-scale wildfires are associated with dry, easterly winds and concurrent drought, the regionally distinct patterns of wind, fuel, fire size, and drought in the 2020 event point to a more complex mechanism than the mere coincidence of wind and drought[11]. A more complex 'recipe' for major westside flames than just wind and drought happening at the same time includes the presence of mountainous areas and valley margins that appear to have affected fire growth and spread. The variation in fire size appears to be partially explained by geographic patterns of wind speed and drought[11]. The general public generally agrees that the main reason for this rise in megafire incidents is climate change, which involves increased human activity and affects drought and extreme heat events.
In addition to the statistical data gathered and examined (Supplemental Table M) to assess the damage to the highway infrastructure of WA, OR, and CA resulting from the 2020 Labor Day wildfires, multiple interviews were held with personnel from each state to enhance the understanding of the impacts of the megafire to their highway systems.
Interviews with WSDOT emergency personnel indicated a focus on the post-fire activities associated with debris flows (slides) and plugged ditches (flooding), which are both attributed to continuous proper maintenance throughout the year. Structural damage seems to be their biggest expense (Supplemental Table S11), but they work with the WA State Department of Natural Resources as well to identify and predict post-fire slide areas along roadways. Replacement of wooden guardrail posts with metal posts is likely to increase resiliency but is expensive and time-consuming to implement. Another resiliency task related to maintaining the highways is removing more hazard trees from around the roads before a megafire. Such actions are currently taking place in the medians of many highways in OR. WA does not maintain a disaster budget and therefore must deal with natural disasters like megafires with the state's funds until they initially assess and provide FHA with the characterizations of the damage and the estimated costs. Once the financial threshold limit has been met for funding, FEMA can then be engaged, and additional financial resources can be requested as well. Another item that stood out during the interviews is that planning too often fails to provide conclusive answers, with success dependent on the extent of the disaster as well as the topography, weather, and elevations of the disasters.
Based on an assessment of interviews among the three states, OR appears to have had the most challenges with dealing with the megafire disasters, simply because they had never encountered the magnitude of facing five megafires simultaneously throughout the state and the amount of destruction that they caused so quickly. In addition, there were already numerous smaller wildfires occurring throughout the state that firefighters and emergency personnel were already battling when the Labor Day wildfires hit. While interviewing ODOT personnel, who participated in the emergency recovery and response effort throughout the state, it was evident that OR was unprepared for such a natural disaster or the amount of devastation it caused. Since OR officials were inexperienced with a wildfire catastrophe of this scale, they chose ODOT to handle the overall recovery operation whether it was related to roads and highways or not, to utilize their experience with handling the response and recovery effort similar to their capital improvement plan (CIP) contractual process. ODOT did reach out to Caltrans for ideas and assistance since they were more acquainted with this type of natural disaster and how to approach the response and recovery operations the most efficiently. The delivery and operations division within ODOT led the work during the response and recovery operations during the megafires throughout the state. The state of OR does maintain a bi-annual contingency budget at the statewide level and each of the five ODOT regions maintain a small budget for emergencies as well, but none were even remotely adequate to address a natural disaster of this magnitude. The emergency operations group within ODOT undertook the challenge of clearing and cleaning up debris from the highways as well as assisting FHA and FEMA in recovering financially from the wildfire disasters. This included ODOT staff first going out to the roads that were being affected and determining how fast they could either get the roads back open and/or what it would take to get the roads opened safely. This was only the first step in the process and the unbudgeted costs incurred here were borne by the state initially. The second step involved completing the DDIRs for FHA. The third step was requesting funds from FEMA, which required additional documentation related to the damage and much more detailed cost data information. Long-term impacts from these wildfires on the highways that ODOT is continually upgrading include a) pavement damage, which involves early cracking from additional heavy equipment on the roads; b) unstable slopes, drainage issues, clearing ditches, and c) removing hazard trees before they become another problem.
Impressions of the interviews indicated that CA officials seem to have the best handle on how to deal with natural disasters, not only because the state maintains a disaster budget, but also because during the interviews it was apparent that they are so accustomed to fires that the 2020 Labor Day event seemed rather unextraordinary. The state of CA maintains an annual reserve set aside for natural disasters, which includes wildfires consisting of hundreds of millions of dollars, which the CA Transportation Commission (CTC) can increase if they deem necessary. Six response/recovery branches within the Office of Emergency Management Division of Maintenance throughout the state collaborates with a specific wildfire task force that continuously works on wildfire preparedness, and they also work with the Office of Vegetation and wildfire Management extensively. On the day when a wildfire starts, Caltrans completes a preliminary major damage assessment (PMDA) form, which then goes through the CA Governor's Office of Emergency Services (Cal-OES) and then onto the federal government. The two avenues of revenue include: a) FHA, with funding initiated by the Governor's state of emergency declaration; and b) FEMA, with funding initiated by a Presidential state of emergency declaration. Caltrans typically only seek reimbursement from the federal government when it makes sense, as disaster funding is built into their annual budget. Caltrans described the same scenario as the WA officials – specifically, that planning cannot anticipate where a disaster will strike or how extensive it will be.
Given the increasing frequency of destructive megafires in the three states and the ensuing destruction and financial effects on highways, the data produced by this work enables the identification of specific highway damage areas and provides a quick and efficient way to estimate the overall financial damage ramifications for local, state, and federal agencies, particularly FEMA and FHA. Some of the challenges encountered in this study included obtaining the research data in the first place, identifying, and decomposing the data into distinct features, and realizing that a large portion of the financial and physical damage data provided for each wildfire was consistently lacking.
As with any research, caution should be exercised in the interpretation of results because of several limitations in the research. Most prominently, data availability continues to be a significant limitation. Although the three states' historical megafire data was examined, and plausible explanations for the 21st century's spike in wildfire activity were assessed, focusing just on megafires may have overlooked additional state-wide highway damage caused by lesser wildfires.
Future research must address these limitations despite the practical benefits of these results. Analysis of additional routes impacted by wildfires that may be smaller in size than megafires within a given geographic area should be part of future research. The positioning of the highways with respect to the size (in hectares burned) of the wildfires constituted another constraint. It could be helpful to conduct additional research to ascertain the extent of financial harm that roadways sustain based on their placement in relation to the wildfire center.
While each state recorded the highway damages and estimated costs, some interpretation was required to align the various damages and their corresponding costs. Data from the DDIRs and DARs were absent for each of the distinctive features examined in the study (hazard trees, slope-rock scaling, structures, and traffic control impacts). Further data in each of these categories would be beneficial for future research.
To prepare for and manage wildfire catastrophes, transportation authorities must understand both the financial and physical components of the damage to the transportation network. Studies of the economic repercussions of catastrophic wildfires must be comprehensive and cover all economic components to have a good knowledge of the true impact of large wildfires, which often exceeds the usual impact indicators. Our work aims to give emergency planners, regardless of their background in transportation, at agencies like WSDOT, ODOT, Caltrans, and other governance emergency management organizations – FHA and FEMA – a clear and concise set of information regarding not only the obvious increase in megafires, but more specifically the physical and financial devastation caused by megafires during the 2020 Labor Day wildfires along the US Pacific coast. The findings will help identify and assess highway damage as well as guide future infrastructure expenditures.
These findings point to the notion that the construction of a standardized, centralized, nationwide database tracking system for reporting the damage from wildfires seems to be sorely needed. Such a database would be similar to that used by the LAHM online portal for recording data on flood-mitigated buildings in Louisiana[46].