To guard against the onslaught of natural disasters, we need to learn the lessons of the past. Authorities should look into how and why the experience gained from similar disasters failed to prevent the deaths of dozens of people in mudslides that engulfed hilly residential areas of Hiroshima — after torrential rains hit in the early hours of Wednesday — so that the extent of damage can be limited in future disasters.

With its largely mountainous terrain, Japan is prone to landslides that cause heavy damage. According to the Cabinet Office, roughly 1,000 reported landslides take place each year on average, and more than 500,000 locations nationwide have been identified as susceptible to landslides.

At least 91 people were killed or listed as missing after the collapse of rain-sodden slopes released torrents of mud, rock and debris that devoured houses built at the foot of mountains in the northern outskirts of the city.