South Carolina Hurricane Evacuation Study: Behavioral Analysis
Lead Investigators: Dr. Susan L. Cutter, Dr. Christopher T. Emrich and Dr. Jerry T. Mitchell
The state of South Carolina updated its 1998 Hurricane Evacuation Study (HES) to account for recent demographic changes in the coastal counties, which influence evacuation-timing scenarios, routes, and published maps. This project assisted the state in Task 5, which requires a behavioral study to provide quantitative data on coastal residents’ likely behavior during hurricane threats. These data are used in shelter planning, transportation modeling, guidance for evacuation decision-making and warning, and public awareness efforts. The HVRI developed the questionnaire and administered the survey to coastal residents, in addition to the collection and analysis of the data. A final written report on the results (including the survey design and methods, analysis, and tabular information) was provided to the state and its federal partners.
Seigler, Wesley Chad, 2014. Analysis of Hurricane Preparedness Levels and Evacuation Intent for South Carolina Coastal Residents, Master's Thesis.
Bowser, Gregg C. and Susan L. Cutter, 2015. Hurricane Evacuation Decision-Making and Behavior, Environment (forthcoming).
In partnership with the United States Army Corps of Engineers (USACE) and the South Carolina Emergency Management Division (SCEMD), USC’s Hazards & Vulnerability Research Institute conducted a survey of coastal residents on their past and potential evacuation behavior in response to hurricanes. Residents in the eight coastal counties in South Carolina were sampled between March-May of 2011 and the results were just released. A total of 3,272 surveys were returned. The survey has a margin of error of +/- 1.71% for the entire study area. The main findings are summarized below:
1. Nearly two-thirds (61%) of the sample is unlikely to evacuate in advance of a Category 1 or Category 2 hurricane. This is worrisome as more than half of the residents sampled lived in either a Category 1 or Category 2 surge zone. This varies regionally along our coast with residents in the southern counties (Beaufort, Colleton, Jasper) more likely to evacuate for such storms (32%), than those in the central region (Berkeley, Charleston, Dorchester) (18%), or northern region (Georgetown, Horry) (12%).
2. For major hurricanes (defined as Category 3, 4, or 5), the anticipated evacuation behavior is better; 77% of the coastal residents in the survey stating they would leave.
3. In addition to residents living in designated hurricane evacuation zones, the survey included people living outside of these formally-defined areas. These so-called shadow evacuations (people living outside of designated evacuation zones, but who participate in evacuations) are a concern. For a major hurricane, the number of shadow zone evacuees could be significant increasing the coastal evacuating population by 100,000 thereby complicating emergency management, extending evacuation times, and potentially putting more people in harm’s way.
4. At least a third of the coastal residents are uncertain or incorrect about their location in or out of storm surge or FEMA-flood zone.
5. More than 90% of the household’s in the survey utilize local television (followed by The Weather Channel and local radio) for evacuation notices and storm updates prior to, during, and after landfall.
6. Mandatory evacuation orders are more effective in prompting evacuations than voluntary recommendations. The use of mandatory evacuation orders increases the likelihood of citizens evacuating for Category 1 or 2 storms by 25%.
7. A significant percentage of evacuating households (95%) said they would bring their pets.
8. The first choice for sheltering in an evacuation is the home of family members or friends (41%), followed by motels/hotels (29%). Less than 10% listed public shelters or pet-friendly public shelters as the first choice.
9. Respondents report a good level of preparedness for hurricanes, with more than 75% saying they had enough supplies to sustain their household for three days or more.
10. Respondents were more likely to evacuate (74%) if they knew they could return within three days. With return periods of one week or two weeks, the willingness to evacuate decreased from 74% to 55% (one week) and from 74% to 45% (two weeks or more).
A full copy of the survey results can be found here (PDF format).