Tokyo Metropolitan Storm Surge Training Site

Tokyo Metropolitan Storm Surge Training Site Top

Why Do Storm Surges Occur?

This page describes the measures taken by the Tokyo Metropolitan Government in response to a storm surge or tsunami.

The sea level rises and falls slowly, approximately twice a day. This is the ebb and flow of the tide.

The ebb and flow of the tide is caused by the gravitational pull of our moon and sun, and by the centrifugal force caused by the rotation of our earth.

Rising sea levels can also occur when typhoons and low atmospheric pressure systems approach and the barometric pressure drops.
(When the pressure lowers 1 hPa, the sea level rises by approximately 1 cm.)
　Strong winds caused by typhoons and low barometric pressure can also blow from the sea toward land thereby raising sea levels even further.
　Storm surges occur when the tide is high, when a typhoon and low-atmospheric pressure cause the atmospheric pressure to drop, and when even stronger winds blow.
If the waves of a storm surge flow into the city going beyond the seawall, a storm surge disaster will occur.

When seawater goes over the seawall, the following damage will occur.

Wooden houses that are located close to the coast are washed away. Houses can be destroyed.
If sea water enters an underground room, or underground shopping area, you will not able to evacuate from the underground shopping area.
There are areas where flooding can continue for a week or longer. Life lines (electricity, gas, water, communications) cannot be used for a long period of time in those areas, making daily life difficult.

【When Do Things Get Dangerous?】

When a typhoon approaches or hits Tokyo.

It becomes even more dangerous when the tide coincides with the time that the typhoon is approaching.

Introduces the coastal conservation facility setup by the Tokyo Metropolitan Government at Tokyo Bay to prevent storm surge disasters.