Identifying vulnerabilities (Step 2 in the risk assessment process) are the locality’s pre-existing characteristics (social, population, lifelines) that may intersect with hazard threats to create risk. Places with higher social vulnerability have a lower capacity to prepare for, respond to, and rebound from disasters. Places with higher population vulnerability simply have more people who will be in need of goods and services during disasters. Higher lifeline vulnerability occurs in places with more community lifeline and critical infrastructure.
Vulnerability (i.e. a locality’s pre-existing characteristics) remains static for each hazard, and is calculated as the average min/max standardized (Xsc=X−XminXmax−Xmin) sum of population density, social vulnerability, and lifeline density scaled (Low 1 – to High 5).
The map below is based on the population data collected from the 2020 American Community Survey (ACS) 5-year product at the block group level.[1] This population data was geo-processed with the ESRI ArcGIS Pro Create Random Points tool to randomly distribute the population (Low- Moderate Universe). Similar to critical infrastructure, this population data was geo-processed with the ESRI ArcGIS Pro-Summarize Within tool, to generate a count of points within each 0.25-square-mile hex grid. The population per hex grid was classified on a quasi-exponential classification scale, showing areas with higher populations across the R2C AOI (see map below).
To spatially apportion population data to the hexagonal grids required that the count of population for each block group be randomly distributed across the applicable block group geographic area of each block group. Like other vulnerability indicators, population data was summed to generate a count of points within each .25-mile hex grid. Population per hex grid was classified on a quasi-exponential classification scale showing areas with higher populations across the AOI (Figure 3). Here we see pockets of higher population in each county including: Cocoa and Cocoa Beach, Melbourne and Melbourne Beach, and Cape Canaveral in Brevard County; the Clermont and Mount Dora areas of Lake County; Ocala in Marion County; Orlando and its suburbs in Orange County; Celebration and Kissimmee in Osceola County; Altamonte Springs, Casselberry, Lake Mary, Longwood, and Oviedo in Seminole County, The Villages in Sumter County; and Daytona, Deland, Deltona, and beach cities/towns in Volusia County. Although all populated (large or small) can be adversely affected by disasters we often see the worst outcomes in places where high populations intersect high hazard areas. Orange and Seminole Counties have the most people in the high population category with 23.8% and 23.4% of their hex grid area (respectively) classified as high population.
The concept of social vulnerability is theoretically framed by a multi-disciplinary litany of case studies and research on specific hazard events, their impacts, and outcomes. Social vulnerability to hazards refers specifically to a lack of ability for individuals and communities to adequately prepare for, respond to, and rebound from environmental hazards. The science of vulnerability is relatively recent, but theoretical links between pre-event socio-economics and general adverse outcomes date back decades. One of the first operational measures of social vulnerability, Maloney’s (1973) Social Vulnerability of Indianapolis linked underlying social characteristics with adverse health outcomes. Subsequently, scholars at the University of South Carolina and the University of Central Florida have driven development of vulnerability science, empirical measurement of social vulnerability, and use of social vulnerability metrics for decision making, planning, and all phases of emergency management practice.
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Following the 2017 Hurricane Season, the Federal Emergency Management Agency (FEMA) produced an After-Action Report[1] utilizing a relatively new construct for disaster planning and response that centers on the stability of critical infrastructure lifelines enabling the continuous operation of critical government and business functions essential to human health and safety or economic security.
Here, FEMA sees lifelines as the integrated network of assets, services, and capabilities used day-to-day to support the recurring needs of the community. FEMA’s community lifelines construct establishes a national standard for disaster response, recovery, and preparedness, including mitigation. The lifelines construct recognizes that communities depend on a network of interdependent systems that involve public and private entities including everything from utilities to hospitals to supermarkets. At any point along the lifeline, a failure can result in a cascading set of negative outcomes (or failures) in other directions.
These lifeline concepts are considered in this assessment with specific emphasis on building an empirical basis for inclusion of community lifelines as part of the vulnerability equation. Stabilizing and protecting community lifelines in catastrophic incidents is vital and requires improved coordination and response structures, reinforced through long-term permanent solutions that mitigate the impact of disaster events.
[1] FEMA. 2017 Hurricane Season FEMA After-Action Report. July 12, 2018. Accessed at: https://www.fema.gov/sites/default/files/2020-08/fema_hurricane-season-after-action-report_2017.pdf
Social vulnerability is calculated using the Cutter et al. (2003)[1] method to identify areas based on their capacity to prepare for, respond to, and rebound from disasters. SoVI for the AOI was generated using UCF's Vulnerability Mapping and Analysis Platform (VMAP). Areas shaded dark and light red have comparatively higher vulnerability and areas shaded dark and light blue have lower vulnerability.