How effective are evacuation orders? An analysis of decision making among vulnerable populations in Florida during hurricane Irma

Abstract

Natural disasters preparedness measures are of paramount importance in reducing fatalities, economic tolls, and health concerns for vulnerable populations. One such preparedness measure that policymakers can take is issuing an evacuation order. Our study focuses on vulnerable populations including people in low lying areas, flood evacuation zones, low income communities, sparsely populated areas, and in manufactured or mobile homes. We analyze the evacuation decision and distance of over 170,000 individuals using passively collected location-based service (LBS) data in Florida before, during and after Hurricane Irma. We control for evacuation order, evacuation order date, and storm path. The results of the analysis are in line with hurricane evacuation studies using survey data, which provides validation that using big data can be a reliable and efficient method to analyze hurricane evacuation decision making. Our major findings are that (1) individuals issued a mandatory order are far more likely to evacuate than if given a voluntary order, (2) manufactured and mobile home residents are more likely to evacuate short distances than site-built home residents but less likely to evacuate longer distances, (3) people living in low income census tracts were less likely to evacuate longer distances than those in higher income census tracts and (4) population, employment and road density were positively associated with decision to evacuate. The authors recommend that policies and hurricane preparation measures pay particular attention to less densely populated and low-income regions as these were identified as vulnerable areas that were less likely to evacuate.

HEvOD: A database of hurricane evacuation orders in the United States

“…Although these studies have provided significant and valuable insights, they are not well suited for policy analysis and design due to limited generalizability and hypothetical bias 8 , 14 – 19 ; this significantly inhibits our ability to systematically evaluate the effectiveness of evacuation orders as a public policy instrument. The prevalence of geotagged social media data and high-fidelity mobility data in the past few years has enabled researchers to, at least partially, overcome hypothetical and sampling biases 20 , 21 . Nevertheless, generalizing the findings beyond limited geography and conducting causal learning and reasoning are still limited due to the lack of a comprehensive, standardized, and high-temporal-resolution record of historical evacuation orders.…”

A data‐driven method for identifying the locations of hurricane evacuations from mobile phone location data

“…Location‐based disaster response studies, like surveys, generally select a study area based on whether or not it was directly impacted by the disaster. Study areas in the current hurricane evacuation literature range from the Houston metropolitan area to examine Hurricane Harvey (Deng et al., 2021; Hong et al., 2021) to the 21 coastal counties most affected by Hurricane Florence (Cheng, 2021; Tao, 2021) to the entire state of Florida to evaluate evacuation patterns during Hurricanes Matthew (Long et al., 2020) and Irma (Darzi et al., 2021; Long et al., 2020; Yabe, Tsubouchi, et al., 2019; Younes et al., 2021). After the study area is selected, researchers attribute all movement patterns from that location matching a specified behavior during a specific timeframe as occurring in response to the disaster.…”

Understanding the Decision-Making Process for Hurricane Evacuation Orders: A Case Study of Florida County Emergency Managers

“…Existing research on events such as volcanic eruptions has shown that how evacuation decisions are communicated to residents and the way these messages are constructed are of paramount importance [31]. In the context of hurricane evacuations, previous studies have mainly focused on evacuation from residents' point of view (see [32], where the authors discussed the evacuation behavior of the vulnerable population during Hurricane Irma), with a few studies mentioning the role of EMs [33]. Evacuation decisions are complex and require a more holistic approach by EMs than a mere assessment of weather reports.…”