The torrential rains that hit wide areas of western Japan since last weekend caused landslides and flooding, resulting in massive damage and leaving at least 110 people dead and dozens of others unaccounted for. The heavy toll came despite a maximum alert issued by the Meteorological Agency Friday evening for torrential rains of an intensity that "had never been experienced before" and that presented "a pressing and grave danger." While search and rescue operations continue for the victims, whether and how the imminent risks posed by the downpours were effectively shared with residents in the areas hit by the disaster, and what actions the residents took for their safety in response to the information provided, should be closely reviewed.

The heavy rain alert issued by the Meteorological Agency for as many as nine prefectures in western Japan called for taking maximum-level caution against severe disasters such as landslides and flooding. The government began issuing such alerts in 2013 based on a lesson from a typhoon that caused heavy damage in the Kii Peninsula in 2011 in which nearly 100 people either died or went missing across the country: that the level of danger posed by the extreme weather may not have been adequately conveyed to the public. The special alert, which is triggered by the forecast of a weather condition that "could happen only once in several decades," must be communicated from prefectural to municipal governments, which in turn must take steps to alert local residents.

But despite evacuation calls by local governments, many of the victims were killed by landslides that buried their houses where they remained for the duration of the torrential rains, while others were swept away by flooding rivers in their neighborhoods — some inside their vehicles as they were trying to escape. That raises the question of how seriously the imminent danger cited in the special alert was taken by residents and whether it prodded them to take action to ensure their safety. As we confront more volatile and extreme weather conditions, what must change is not just the way disaster-related information is announced and communicated by government authorities, but the mindset of residents who need to act on the information.