  Major disasters such as extreme weather events can magnify and exacerbate
pre-existing social disparities, with disadvantaged populations bearing
disproportionate costs. Despite the implications for equity and emergency
planning, we lack a quantitative understanding of how these social fault lines
translate to different behaviors in large-scale emergency contexts. Here we
investigate this problem in the context of Hurricane Harvey, using over 30
million anonymized GPS records from over 150,000 opted-in users in the Greater
Houston Area to quantify patterns of disaster-inflicted relocation activities
before, during, and after the shock. We show that evacuation distance is highly
homogenous across individuals from different types of neighborhoods classified
by race and wealth, obeying a truncated power-law distribution. Yet here the
similarities end: we find that both race and wealth strongly impact evacuation
patterns, with disadvantaged minority populations less likely to evacuate than
wealthier white residents. Finally, there are considerable discrepancies in
terms of departure and return times by race and wealth, with strong social
cohesion among evacuees from advantaged neighborhoods in their destination
choices. These empirical findings bring new insights into mobility and
evacuations, providing policy recommendations for residents, decision makers,
and disaster managers alike.

Physics and Society;Applications