What are the stages of typhoon defense?

Typhoon is a typical disastrous weather process and one of the most serious meteorological disasters. Because the typhoon is big and powerful, the defense of typhoon meteorological disasters is also the most complicated. Generally speaking, typhoons are generated at sea and often land on the move, affecting coastal and even inland areas. According to the different development stages and influence areas of typhoons, typhoon defense can be roughly divided into the following three stages.

The first stage: the defense of strong winds and wild waves at sea. 2065 438+02 08 02 Fishermen in Longgang Town, Cangnan County, Zhejiang Province reinforced fishing boat ropes at the dock on the eve of the landing of two typhoons, Sura and Davi.

At this stage, it is mainly to strengthen the defense of ships, fishing boats and offshore oil platforms. Because the wind force of typhoon (tropical cyclone) at sea is often above 8- 10, even above 12, and the sea area near the typhoon center is a rotating wind, accompanied by waves and wolves several meters or even higher, ordinary ships can't resist it.

For ships, the best preventive measure is to leave quickly. At this time, we should pay special attention to the "typhoon early warning and forecast", especially the typhoon center position, center strength, moving speed, moving direction and wind circle radius. Because it determines how to evacuate and where to go.

One thing should be specially reminded: the typhoon moves at a slow speed of 5- 10 km/h and at a fast speed of 25-30 km/h, which is generally inaccessible to small and medium-sized fishing boats. Although the ship may have this speed, once the typhoon is formed and strengthened, it will often form a gale circle with a diameter of hundreds of kilometers around it. Therefore, once the typhoon warning is received, the operating ship should leave quickly and return to Hong Kong to avoid danger.

The second stage: the defense of strong wind and rain along the coast and land during typhoon landing. This is a huge wave from the seawall of Houqi, Qinyu Town, fuding city, where the typhoon landed (photo taken on August 3rd). At about 6: 50 on August 3rd, Typhoon Sura landed on the coast of Qinyu Town, fuding city, Fujian Province, with the maximum wind force 10 (25m/s) near the center.

During the landing of typhoon, due to the influence of topography, the wind and rain will be very heavy, and it is often accompanied by storm surge and storm surge. At this time, the defense focus is: the life and property safety of ships, port facilities, coastal towns, villages, offshore aquaculture and other personnel in the port.

The defensive measures include: the ships in the harbor are fixed and the personnel on board are evacuated; Strengthen port facilities, dismantle higher equipment and move indoors as much as possible; People in coastal towns and villages reduce going out (school holidays, leaving work early, canceling travel plans) and move to high places and safe and solid buildings; Strengthen livestock sheds, breeding box nets, etc. Turn off electrical equipment and cut off unnecessary power supply in time; Stay away from poles, billboards, trees and other dangerous things (trees are easy to fall down in strong winds after soaking).

The "typhoon warning signal" issued by the meteorological department is mainly aimed at the strong winds at sea and coastal land in the above two stages. For example:

Typhoon blue warning "The average coastal or land wind force is above 6 or the gust is above 8 within 24 hours." ;

Typhoon yellow warning: "The average coastal or land wind force is above 8 in 24 hours, or the gust is above 10." ;

Typhoon orange warning "12 hours, coastal or land average wind 10 or above, or gust 12 or above." ;

Typhoon red warning: "The average coastal or land wind power 12 or gust 14 or more in 6 hours."

The third stage: the typhoon weakened and went deep into the land, causing heavy rainfall in the inland. Pay attention to prevent floods, mudslides, landslides, dams and other disasters.

On August 4th, cadres of Haicheng Small Wharf in Anshan City, Liaoning Province visited the dam to help themselves. Influenced by "David", from the early morning of August 3, heavy rains fell in Anshan, Yingkou and Huludao, Liaoning Province. On the way to the disaster area, the reporter saw that local cadres and masses and army officers and soldiers began to carry out flood fighting and self-help work. Xinhua News Agency reporter Yang Qing photo

The weakened typhoon still carries rich warm and humid air after landing. After it goes deep into the land, it interacts with the relatively cold air over the land, often causing inland rainstorm, heavy rainstorm and even extremely heavy rainstorm, as well as strong weather such as thunderstorms and local tornadoes, which can easily lead to meteorological disasters and derived disasters such as floods in mountainous areas, mudslides, landslides, urban and rural floods, small and medium-sized river reservoirs, ponds and dams.

At this stage, with the weakening of typhoon intensity and the stop of numbering, the typhoon warning signal will often be lifted. At this time, we should pay special attention to the "rainstorm warning signal" issued by the meteorological department and the "geological disaster warning information" jointly issued by the meteorological department and the land and resources department, and timely transfer the people living and stranded at the bottom of the ditch, downstream of the reservoir dam, the edge of the dry river bed and the low-lying areas in urban and rural areas.

I hope to learn more defense knowledge and minimize losses.