Jay Baker Department of Geography Florida State University Mike Lindell Institute for Hazard Mitigation Planning and Research University of Washington March 2018
The findings in the presentation are based on surveys. • Not all surveys are created equal. • A good survey has a representative sample of a risk area population and asks questions that are theoretical based and practically significance. We will begin with a broad framework. • What do we mean by evacuation? • What does 50 years of research on a wide variety of hazards show are the major variables that influence household protective actions and how do these variables fit together in a coherent model? • What are the most important variables affecting hurricane evacuation? We will then turn to a number of specific findings from hurricane evacuation research. We will conclude with a summary of the most important issues for emergency managers and evacuation transportation managers.
Leaving one’s home to go someplace safer • Leaving a surge-defined evacuation zone • Leaving a structure that would be unsafe from wind Mobile homes “Substandard” housing • Other considerations (e.g., loss of electric power)
Principal evacuation behaviors • Leaving or staying • Departure timing • Vehicle use • Evacuation route choice • Type of accommodations • Evacuation destination • Reentry
Environmental Situational cues facilitators Threat perceptions Social Information cues Pre-decision search Behavioral response processes Protective strategy • Information search Information • Exposure action • Protective response sources • Attention perceptions • Emotion-focused coping Protective • Comprehension action decision Information making channels Stakeholder perceptions Situational impediments Warning messages Personal characteristics • Physical/psychological, material, social/ Social/ political, and economic resources environmental • Past experience context • Demographic attributes 5
Intensity 99% Traffic Jams Business Closing Consistency Peer Evacuating White Official Warning Environmental Cues HHSize Hispanic Risk Area Marital Property Protection Education Evac Expense Mobile Home Income Black Surge Risk 66% Looting Nearby Landfall Coastal Tenure HrrExperience Child Age Wind Risk Flood Risk Casualties Homeowner UnnExperience Female Job Disruption Correlation 33% 0.00 Authorities 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 Rapid Onset Peers + Positive Impact News Media − Negative Impact X Nonsignificant Impact + Positive Impact (Less studied) − Negative Impact (Less studied) Service Disruption X Nonsignificant Impact (Less studied) 0%
Model of Evacuation Participation Hurricane Katrina/Rita Evacuation Model
Evacuation in Wilma in Lee County, FL • Mobile home residents are more likely than 100 residents of site-built 90 homes to evacuate. 80 70 60 Percent 70 • In this example 50 MAINLAND mobile 40 48 homes evacuated more 30 than site-built homes on 20 ISLANDS. 10 0 Mainland MH's Island Site Built
Effect on Evacuation in Andrew • After taking into account a person’s Mobile Home Heard Must Go housing type, Beach evacuation zone, and Heard Should Go hearing evacuation Expect Flooding notices, demographics Had Plan have relatively little Mainland Surge (-) Black effect on evacuation in 10 Years in Region (-) most locations. Age Live Alone (Data from Florida) Kids Pets Income Other Ethnic 0 5 10 15 20 25 30 35 40 45 50 Magnitude of Effect
• Participation rate increases with storm Table 1: Smoothed percentages of h ouseholds expecting to evacuate for hurricanes in Category One through category within each risk Category Five, by Risk Area. area. Risk Category Category Category Category Category • Participation rate Area One Two Three Four Five decreases with risk area 1 45.9 63.7 87.8 98.2 100.0 within each storm category. 2 35.9 53.7 77.8 88.2 91.4 3 31.1 48.9 73.0 83.4 86.6 • There is incomplete 4 28.2 46.0 70.1 80.5 83.7 compliance (everything 5 26.5 44.3 68.4 78.8 82.0 in the red boxes should be 100%) and shadow Source: Lindell and Prater (2007) evacuation (everything outside the red boxes should be 0%).
Identified Correct Evacuation Zone • People in most regions Cat 1 and 3 Zones by Florida Region Percent of All Respondents in Evacuation of Florida can’t correctly indicate the evacuation 100 zone in which they live. 90 80 • Labels below the 70 Zone graph refer to planning 60 regions of Florida – West 50 Florida through 40 Northeast Florida. 30 20 • SE Florida’s Cat 1 10 zone boundary was 0 WF AP NC WC TB SW SE TC EC NE more simple than others. Cat 1 Zone 11 16 17 21 33 15 58 12 28 18 Cat 3 Zone 21 11 5 7 13 6 13 6 28 3
• People living in more vulnerable areas are Tampa Bay Evacuation in Charley more likely than others to by Zone evacuate. 60 • Still, rates are too low 50 in the most vulnerable 40 areas and too high in the Percent less vulnerable areas. 30 20 • Mandatory evacuation orders were issued for 10 Zone A. Orders varied 0 among counties in other A B C D E zones. The NHC forecast track was for this location until shortly before landfall.
• The risk area boundaries in this map are derived almost directly from SLOSH. • Consequently, they have a sound scientific basis. • However, these boundaries make it very difficult for most people to determine which risk area they live in.
Source: Arlikatti et al. (2006) • Texas coastal residents are very inaccurate in judging which risk area they are in —even when given a map such as the one on the previous slide.
Evacuation in Floyd Site-built Homes • Too few people usually evacuate from 100 the most vulnerable 90 areas. 80 • Too many people 70 usually evacuate from 60 relatively safe areas. 50 • In Floyd mandatory 40 orders were issued for 30 almost all of the cat 1-2 20 zones, some of the cat 3-5, but for none of the 10 other areas. 0 Cat 1-2 Cat 3-5 Non-surge Non-coastal
This map is relatively good because evacuation zone boundaries are defined by recognizable features such as roads.
Examples of Evacuation Zones • The risk area boundaries in this map are defined by ZIP codes. • This works well in densely populated areas where ZIP codes cover small areas • It does not work well in sparsely populated \areas where a ZIP code includes areas with very different elevations.
Evacuation by Official Notice H • People are more likely Cat 1 Othr Surge to evacuate if they 100 100 Percent of Respondents Percent of Respondents believe they have been told to do so by public 50 50 officials. 0 0 • Graphs at right show None Should Must None Should Must the effect within each of Non-surge Non-coastal 100 100 four risk zones. Bars Percent of Respondents Percent of Respondents indicate % evacuating in 50 50 each group. (Data from Floyd) 0 0 None Should Must None Should Must
• Too few people in Heard Officials Say Evacuate evacuation zones say Cat 1 Surge Zone they hear evacuation notices. Evacuation Eastern NC was ordered in all Cat 1 Southeastern NC zones at right except Myrtle Beach SC Charleston SC SE FL. Beaufort SC Savannah GA Brunswick GA • Too many people Northeast FL outside evacuation East Central FL zones say they hear Treas. Coast FL evacuation notices. Southeast FL 10 20 30 40 50 60 70 80 90 100 (Data from Floyd) Percent of Respondents
Evacuation in Lili in Louisiana 100 • The combined effect of 90 hearing mandatory 80 evacuation notices AND believing that one’s 70 Safe, Heard home would be unsafe Nothing 60 Unsafe, Heard can be very large. Must 50 40 • Bars indicate the percent evacuating in 30 each group. 20 10 0 Coastal Parishes Adjacent Parishes
Reasons Given for Not Evacuating in Floyd by Income • Most people who don’t evacuate fail to do so 100 because they don’t No Transport 90 believe they need to, not No Place to Go 80 Percent of Income Category Felt Safe because of constraints to 70 leaving. 60 50 • This is true even for low 40 income households in 30 most locations. 20 10 0 LT $15K GT $15K Income
Hazard of Greatest Concern in Sandy by Stated Proximity to Water 100 • Most people are more 90 concerned about WIND 80 than other hazards – 70 even those close to Other water. 60 Don't Know Percent 50 Tornadoes Rainfall Flooding 40 Wind+Surge 30 Surge/Waves 20 Wind 10 0 LTE 1 Block GT 1 Block
Evacuation by Perceived Safe in 125 MPH Hurricane • People who believe Cat 1 Othr Surge in 125 MPH Hurricane in 125 MPH Hurricane their homes would be Percent of Respondents 80 Percent of Respondents 80 unsafe if struck by a 60 60 hurricane are more likely 40 40 than others to evacuate. 20 20 0 0 Safe Not Safe Safe Not Safe • Graphs at right show the effect within each of Non-Surge Non-Coastal in 125 MPH Hurricane in 125 MPH Hurricane four risk zones. Bars Percent of Respondents 80 Percent of Respondents 80 show % evacuating in 60 60 each group. 40 40 20 20 0 0 (Data from Floyd) Safe Not Safe Safe Not Safe
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