Recent torrential rains took the lives of 17 people in Yamaguchi Prefecture and 22 others in Hyogo, Okayama and Tokushima prefectures. This highlights the importance of municipal actions in securing the safety of local residents during heavy rain.

After more than 200 people died or went missing across the nation in typhoons and torrential rains in 2004, the central government worked out a guideline for judging when to issue warnings or evacuation orders and for manuals on how to disseminate the information. It then handed the guideline to the nation's municipalities.

Many municipalities do not have the manuals yet. They should obtain them as soon as possible. They should also examine local topography and tell residents in advance where to evacuate and what they should be careful of when evacuating in torrential rains.

The recent torrential rains show that municipalities are likely to face difficulty in deciding what to do in an emergency situation. In the town of Sayo, Hyogo Prefecture, where 18 people died and two others went missing, the rains were incredibly strong. The Aug. 3-11 rainfall total reached 349.5 mm, with half of the rainfall concentrated during a three-hour period on the evening of Aug. 9. An extremely strong rainfall of 89 mm per hour was recorded.

On the night of Aug. 8, water levels of the Sayo River rose rapidly beyond expectations, sending the town hall into confusion. After the water levels reached dangerous levels, it took one hour and 20 minutes to issue an evacuation order.

In one area of the town where eight people died, four of them apparently started evacuating toward a primary school building before the evacuation order was issued. But they were washed away and died. Some people stayed at home and were safe. In a torrential rain the situation can change quickly, making judgment on whether to evacuate very difficult.

Moving on flooded surfaces can be very dangerous, especially when the depth of the water rushing by tops 20 cm. When facing such conditions, individuals must ultimately rely on their own common sense and sound judgment.