Rationality of Not Evacuating During Disasters

One month after the August 2026 Chiba heavy rains, Chiba Prefecture is summarizing the event. The number of flooded properties reached over 7,000, with 13 fatalities. The initial estimate of over 2,700 flooded vehicles was clarified to only include vehicles left on public roads. According to reports from non-life insurance companies, nearly 17,000 vehicles are undergoing insurance claim reviews, believed to be due to large-scale flooding of parking spaces in low-lying areas. Six of the deceased drowned in underpasses or flooded public roads in low-lying areas. After the disaster, the Chiba National Highway Office imposed traffic restrictions simultaneously with the activation of Level 4 alert, and the prefecture is now considering the possibility of additionally closing prefectural and municipal roads. Furthermore, at least five of the deceased are confirmed to have died in accidents while walking on the street. Witness accounts state they were swept away while clinging to a utility pole or fell into a ditch or irrigation channel after losing their footing. In response, the prefectural governor reiterated the understanding that while evacuation is standard in disasters, evacuation actions themselves can lead to increased damage, urging comprehensive judgment as designated evacuation centers may also be located in low-lying areas. The disaster occurring late at night also proved unfortunate. Walking through flooded areas in the dark carries considerable risk. The prefecture took measures such as emergency opening of the prefectural office, so the danger of walking through flooded areas should be recognized anew.