Typhoon is a kind of powerful tropical cyclone generated on tropical ocean surface. When the maximum average wind speed at the bottom center reaches 10.8~17.1m/s (wind-force: 6~7), it is called opical Depression; when the wind speed reaches 17.2~24.4m/s (wind-force: 8~9), it is called ropical Storm; when the wind speed reaches 24.5~32.6m/s (wind-force: 10~11), it is called evere Tropical Storm; when the wind speed reaches 32.7~41.4m/s (wind-force: 12~13), it is called yphoon; when the wind speed reaches 41.5~50.9m/s (wind-force: 14~15), it is called siolent Typhoon; and when the wind speed is no less than 51.0m/s (wind-force 16 or higher) , it will be called super Typhoon.

Tsunami contains four types: seismic tsunami induced by submarine earthquakes, volcanic tsunami induced by volcanic explosions, landslide tsunami induced by submarine landslides and storm tides caused by climate changes. The seismic tsunami refers to a kind of abnormal high tides on the coast caused by strong sea water disturbances due to severe submarine relief changes when seaquakes occur at the bottom.

Storm tide is such a phenomenon that the tidal levels in affected areas greatly exceed ordinary levels due to severe atmospheric disturbances, such as strong winds and great atmospheric pressure changes, causing sea water level rises and falls. According to natures of the storms, the storm tides can be classified as typhoon storm tide induced by typhoons and temperate storm tides induced by extratropical cyclones. The former often occurs in summer and autumn, featuring strong, rapid, and powerful with great destruction, typhoon storm tides may occur in all areas having typhoons in coastal areas. While the latter usually occurs in spring and autumn, sometimes in summer, featuring steady surge water accretion, water accretion levels lower than that of typhoon storm tides, which mainly occurs in coastal areas of middle latitudes, such as northern sea coastal areas in our country.

Typhoon, tsunami, storm tide can cause great losses to coastal areas, for example, between August 28th and September 1st of 1992, a severe storm tide disaster hit the east coasts of our country which has the most extensive influence and losses since 1949, due to combination of No.16 Severe Tropical Storm and astronomical tides. This tide disaster spread to Fujian, Zhejiang, Shanghai, Jiangsu, Tianjin, Hebei and Liaoning etc. the comprehensive impacts of storm tides, huge waves, strong winds and heavy rain resulted in attacks to different degrees to ten thousands kilometers of coastal lines from Dongshan Island in Fujian Province to the coasts of Liaoning Province, causing more than 20 million people suffered, 194 dead, 1170km sea dykes damaged, 1.933 million hectares farm lands affected, including 333,000 hectares damaged, the direct economic losses reached more than 9 billion yuan. As a further example, the tsunami in Indian Ocean induced by seaquakes in December 26th of 2004, causing tremendous personal death and property losses to Indonesia, Sri Lanka, Thailand, India, Maldives etc. with 156,000 people dead.

Shanghai, close to East Sea, suffers many typhoons each year, sometimes suffers storm tides with no exception of occurrence of earthquake tsunamis. Therefore, we should strengthen protections against typhoons, tsunamis and storm tides.

Organize the public to carry out protections against typhoons, tsunamis and storm tides mainly by taking following measures: First, transfer the public, before the coming of typhoons, tsunamis and storm tides, organize the public in dangerous coastal areas to transfer to safer areas, and transfer people in dangerous houses to strong houses. Second, stop operations and evacuate. Inform all varieties of boats and ships to stop operations and enter into sheltering harbors, and suspend working at heights, farm works and outdoor activities when typhoons come, if necessary, middle schools and primary schools, kindergartens shall suspend classes. Third, organize to reinforce or dismantle objects in heights vulnerable to falling and construction structures; reinforce or dismantle (remove) advertising boards, flower pots on roofs and windows as well as scaffolds etc. to prevent collapsing and injuring people in winds. Four, inform the public to carry out self protections, like close doors and windows, do not conduct activities at dangerous coastal areas or in outdoor areas etc.