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Safety and Disaster Prevention: Typhoons and Heavy Rain


The areas of low pressure that occur over tropical seas are called tropical cyclones, and a tropical cyclone that is in a low pressure area in the northwest Pacific or South China Sea, and whose maximum wind velocity is equal to or greater than 17 m/second (category 8), is called a typhoon.

Torrential Rain

Characteristics of Torrential Rain

Natural disasters that occur as a result of the rainy season and typhoons exert a great influence on the lives and property of the people and occur every year in Japan. On occasion, the amount of rainfall in one day can be the usual amount for one month. In such cases, river flooding, landslides, etc. can occur, and the lives of residents are endangered. Flood warnings and torrential rain warnings are issued, so it is important that one pays attention to weather reports.

Rain patterns in relation to natural disasters

Simple classification of rain patterns:

  1. Short, heavy spans of rain (1 to 2 hours)
  2. Long periods of rain
  3. Long periods, with heavy spells

Previous natural disasters are nearly always attributable to the third pattern of rainfall.

The criterion for a natural disaster occurrence is said to be when the amount of rainfall for one day exceeds about one-twentieth the average yearly precipitation (Kyoto: 1,545.4 mm).

Heavy Rain from Typhoons

When a typhoon is approaching Japan and there is a seasonal or autumnal stationary rain front in home waters, heavy rainfall may occur even if the typhoon remains relatively far away. In this case, the rain will often continue for a long period, and when the typhoon crosses over Japan, heavier rain and larger natural disasters may occur.

If you feel that you are in danger


If you feel that you are, even slightly, in danger after listening to news or weather reports, try to evacuate to safety as soon as possible.