Population activity recovery: Milestones unfolding, temporal interdependencies, and relationship with physical and social vulnerability

Understanding sequential community recovery milestones is crucial for proactive recovery planning and monitoring and targeted interventions. This study investigates these milestones related to population activities to examine their temporal interdependencies and evaluate the relationship between recovery milestones and physical (residential property damage) and socioeconomic vulnerability (through household income). This study leverages post-2017 Hurricane Harvey mobility data from Harris County to specify and analyze temporal recovery milestones and their interdependencies. The analysis examined four key milestones: return to evacuated areas, recovery of essential and non-essential services, and the rate of home-switch (moving out of residences). Robust linear regression validates interdependencies between across milestone lags and sequences: achieving earlier milestones accelerates subsequent recovery milestones. The study thus identifies six primary recovery milestone sequences. We found that socioeconomic vulnerability accounted through the median household income level, rather than physical vulnerability to flooding accounted through the property damage extent, correlates with recovery delays between milestones. We studied variations in recovery sequences across lower and upper quantiles of property damage extent and median household income: lower property damage extent and lower household income show greater representation in the “slowest to recover” sequence, while households with greater damage and higher income are predominant in the group with the “fastest recovery sequences”. Milestone sequence variability aligns closely with income, independent of physical vulnerability. This empowers emergency managers to effectively monitor and manage recovery efforts, enabling timely interventions.