Estimating pre-impact and post-impact evacuation behaviors – An empirical study of hurricane Ida in coastal Louisiana and Mississippi

Evacuation after hurricane impacts appear (post-impact evacuation) has been underemphasized in empirical evacuation studies. This study uses well-examined factors for pre-impact evacuation and novel factors for post-impact evacuation in a sequential logit model for pre- and post-impact evacuation choices. Results show that the evacuation warning is the only factor that affected both pre-impact and post-impact evacuations. Demographics and housing characteristics are significant factors for pre-impact evacuation but not for post-impact evacuation, while residential damages and durations of utility outages are significant situational factors for post-impact evacuation. The durations of water and power outages had additive effects on the probability of evacuating after hurricane impact. Based on the results, we argue that the conventional assumption that sheltered-in-place residents will remain in the affected area, and the restoration planning and assistance generated with that premise will not be aligned with the demand of residents facing inhabitable living situations with damaged residences and prolonged utility outages. Agencies should consider extending the evacuation planning time horizon for storm events likely to induce severe damages and outages and prepare for evacuation during disrupted conditions.