This study investigates the influence of individuals’ social connections in their decision to either evacuate or not evacuate in the days preceding the landfall of Hurricane Irma. Using Hurricane Irma in September 2017 as a case study, a survey was conducted on two groups (those who evacuated and those who did not evacuate) to assess people’s social connections specifically examining three dimensions: dependability, density, and diversity. These variables, together with socioeconomic variables (e.g., race/ethnicity, age, education), were considered in order to better explain the influences on evacuation decision-making. To collect accurate ephemeral decision-making data from evacuees, the surveys were completed during the evacuation for those who evacuated and shortly after the passage of Hurricane Irma for those who did not evacuate. Through statistical analyses, it was concluded that density and diversity of people’s social networks played a significant role in the decision to evacuate or not, with evacuees having more dense and diverse relationships. On the other hand, the perceived dependability of a person’s social connections (i.e., their perceived access to resources and support) did not significantly impact the decision to evacuate for Hurricane Irma. This study has important implications for adding to the knowledge base on community-based sustainable disaster preparedness and resilience.

For decades, meteorologists and governments have been warning communities in coastal areas for an imminent tropical cyclone (TC) using the Saffir-Simpson Hurricane Wind Scale (SSHWS). The SSHWS categorizes a TC based on its maximum wind speed, and is used in defining evacuation strategies and humanitarian response. However, the SSHWS considers only the wind hazard of a TC, whereas a TC can also cause severe conditions through its high storm surges and extreme rainfall, triggering coastal and inland flooding. Consequently, the SSHWS fails to mirror the TC’s total severity. This becomes evident when looking at past events such as Hurricane Harvey (2017), which was classified as a Tropical Storm while it caused widespread flooding in the Houston (TX) area, with precipitation totals exceeding 1.5 m. Without including storm surge and rainfall information, adequate risk communication with the SSHWS can be challenging, as the public can (mistakenly) perceive a low-category TC as a low-risk TC. To overcome this, we propose the new Tropical Cyclone Severity Scale (TCSS) that includes all three major TC hazards in its classification. The new scale preserves the categorization as used in the SSHWS, to maintain familiarity amongst the general public. In addition, we extend the scale with a Category 6, to support communication about the most extreme TCs with multiple hazards. The TCSS is designed to be applied on a local-scale, hereby supporting local-scale risk communication efforts and evacuation strategies prior to a TC landfall. The scale can be used for risk communication on both the total TC risk and on the categories of the separate hazards, which can be valuable especially in cases when one hazard is the predominant risk factor, such as excess rainfall triggering flooding.

This study conducted in Florida examines the relationship between an individual’s social connections and their decision to evacuate during a hurricane warning. Using Hurricane Matthew in 2016 as a case study, a survey was conducted on two groups (those who evacuated and those who did not), assessing one’s social connections considering three dimensions: dependability, density, and diversity. These factors, in addition to socioeconomic variables (e.g., age, race, education), were used to better define a picture for what influences evacuation decision-making. To avoid memory decay, the surveys were completed at the time of the evacuation for those who evacuated and immediately after the passage of Matthew for those who did not evacuate. It was concluded, through statistical analyses, that the perceived dependability of a person’s social connections (i.e., their perceived access to resources and support) played a significant role in the decision to evacuate or not, with non-evacuees having more dependable relationships and having a tightknit community they can rely on during a storm event. On the other hand, the density and diversity of peoples’ social connections did not significantly impact the decision to evacuate. This study has important implications for adding to the knowledge base on community-based sustainable disaster preparedness and resilience.

Understanding the factors that influence evacuation decision-making among local residents is of critical importance to those involved in monitoring and managing weather-related hazards. This study examined both geophysical and social variables that we believe influenced individual decision-making on whether to stay home, seek out a public shelter, or leave the area entirely during Hurricane Irma. A 23-item survey was administered to a convenience sample of adults (n = 234) who resided within a coastal Florida county that received an evacuation warning during Hurricane Irma in 2017. Results suggested sources of information relied on through media, government, family, and social networks contributed to differences in evacuation behavior. Moreover, potential exposure to weather-related conditions, such as flooding and strong winds, along with the likelihood to use available social resources, also influenced decisions to stay or leave the threatened area. Finally, prior evacuation behavior was significantly associated with the decision to evacuate during Hurricane Irma. The decision to evacuate for Hurricane Irma was shown to impact decision-making to evacuate for major hurricanes in the future. If these findings are applied to future storms, a broader conclusion can be made that residents in vulnerable areas may be more likely to evacuate for major hurricanes than they were in the past. Improved understanding of evacuation decision-making can assist emergency managers in preparation and planning to reduce casualties resulting from a hurricane or other weather-related hazard.

Hurricanes Isaac (2012), Harvey (2017), and Irma (2017) were storms with different geophysical characteristics and track forecast consistencies. Despite the differences, common themes emerged from the perception of track forecasts from evacuees for each storm. Surveys with a mixture of closed and open-ended responses were conducted during the evacuations of each storm while the storm characteristics and decision-making were fresh in the minds of evacuees. Track perception accuracy for each evacuee was quantified by taking the difference between three metrics: perceived track and official track (PT − OT), perceived track and forecast track (PT − FT), and home location and perceived track (HL − PT). Evacuees from Hurricanes Isaac and Harvey displayed a tendency to perceive hurricane tracks as being closer to their home locations than what was forecast to occur and what actually occurred. The large sample collected for Hurricane Irma provided a chance to statistically verify some of the hypotheses generated from Isaac and Harvey. Results from Hurricane Irma confirmed that evacuees expected a storm to be closer to their home locations after controlling for regional influences. Furthermore, participants with greater previous hurricane experience perceived a track as being closer to their home locations, and participants residing in zip codes corresponding with nonmandatory evacuation zones also perceived tracks as being closer to their home locations. These findings suggest that most evacuees from hurricanes in the United States appear to perceive storms as being closer to their home locations than they are and overestimate wind speeds at their homes, thus overestimating the true danger from landfalling hurricanes in many storms.

Since the onset of the COVID-19 pandemic, decision-making during disasters fundamentally changed to accommodate the combined risks of hurricanes and infectious diseases. Prior research conducted in 2020 by Collins et al. examined how individuals changed their intended evacuation decision-making during the pandemic or their actual evacuation decisions during Hurricanes Laura and Sally. Hurricane Ida provided further data on evacuation decision-making when vaccinations and masks were widely available. A digital survey was disseminated to individuals affected by Hurricane Ida in 2021. Respondents provided information about their actual evacuation choices and perceptions of public shelters and COVID-19 risks. In comparison with the 2020 hurricane season, more individuals have reduced negative perceptions of hurricane shelters. However, individuals were less likely to utilize public shelters than in the 2020 season, with 11.4% more individuals stating they would definitely or probably avoid using shelters in 2021. Fewer individuals identified that COVID-19 was a primary reason they chose to stay home during Hurricane Ida (19.5% as compared with 86.8% during Hurricanes Laura and Sally). Furthermore, respondents with health risks for severe COVID-19 symptoms were no more likely to evacuate than those respondents who had no health risks. Potentially, as the pandemic progressed and vaccine availability and COVID-19 management improved, COVID-19 has had less impact on evacuation decision-making. The results from this work should guide planners in emergency management and public health in future hurricane seasons and future pandemics or other outbreaks to anticipate behavior changes and properly manage infectious disease threats.