Meteorological risk early warning of geological disasters： a special early warning of life and death

　　"It is predicted that the meteorological risk of geological disasters will be high in some areas of Ludian, Qiaojia and Ya ‘an, Sichuan from 20: 00 on August 5 to 20: 00 on August 6 …" After the Ludian earthquake, the earthquake area continued to rain, and the local terrain was complex, so the meteorological risk warning of geological disasters jointly issued by the Ministry of Land and Resources and the China Meteorological Bureau attracted special attention. After the Ludian earthquake, the Public Meteorological Service Center of China Meteorological Administration started the refined service at the first time, updated it according to the latest local topography, and produced a special report on meteorological risks of geological disasters in this area. The clear division of risk areas is obvious. So, how was this warning made? What preventive measures should be taken after receiving the early warning?
　　Zhang Guoping, senior engineer of the Public Meteorological Service Center of China Meteorological Administration, told the reporter: "The main meteorological factor affecting the occurrence of geological disasters is precipitation. Therefore, the two major factors we consider when making early warning and forecasting are precipitation and underlying surface conditions. "
　　There are generally two kinds of precipitation. One is the accumulated precipitation actually acting on the underlying surface: the accumulated precipitation in a certain period of time can change the underlying surface and increase the risk of geological disasters; The second is to stimulate rainfall. Under the action of stimulating rainfall, the quantitative change is finally transformed into qualitative change, which leads to geological disasters. The specific situation of the underlying surface determines how much precipitation will cause disaster. "In the earthquake zone, it is necessary to downgrade the precipitation when making meteorological risk warning products for geological disasters, because the soil structure in the earthquake zone is more loose. Generally, 25 mm precipitation may lead to geological disasters, and 10 mm precipitation may induce geological disasters." Zhang Guoping told reporters.
　　"After comprehensive consideration of precipitation and underlying surface conditions, the meteorological risk level of geological disasters can be obtained by numerical model calculation and comparison with the statistical data of historical disaster points." Zhang Guoping said. At present, the public meteorological service center is still gradually developing the earthquake-resistant body, building carrying capacity, population density and so on into the calculation range. If these elements can be considered in the calculation, the risks brought by geological disasters can be calculated more carefully.
　　Like many meteorological warnings, the meteorological risk warning of geological disasters is divided into four levels: red, orange, yellow and blue. However, the destructive power of geological disasters is extremely strong, and its early warning is related to the life safety of everyone in the hidden danger point of disasters. Therefore, the emergency measures of early warning also have its special side. Usually when the risk level reaches yellow or above, the meteorological risk warning of geological disasters will be released through television, radio, network, emergency system platform and even township meteorological information service stations. This is because the main methods to deal with geological disasters are to organize evacuation, transfer and evacuation, and evacuation itself will have a greater impact on the local area, so it cannot be easily started. If the risk is very low, early warning may cause unnecessary panic.
　　With the release of early warning, the local authorities will also take corresponding measures, such as paying close attention to the rain, strengthening inspection and monitoring, stopping outdoor work near hidden danger points, organizing rescue teams, and implementing traffic control. Practice has proved that the most effective way to deal with geological disasters is "transfer and evacuation".
　　"According to the specific situation in different places, the early warning level of the transfer is different. Most provincial early warning regulations require that evacuation preparations be made when a red warning is issued." Zhang Guoping told reporters, "However, some provincial early warnings clearly stipulate that the hidden danger points in the red early warning zone should be evacuated immediately. Taking Fujian as an example, the province’s early warning response stipulates that when the meteorological risk warning level of geological disasters is red, all the people in the hidden danger points, dangerous areas and high-risk areas of geological disasters in the early warning area should be transferred to disaster avoidance points and safety areas; People in non-geological hazards, dangerous areas and prone areas should also be prepared to transfer at any time. "
　　In recent years, the transfer of personnel after the meteorological risk warning of geological disasters has saved thousands of public lives. On August 13th, 2010, a catastrophic flash flood and debris flow caused by heavy rainfall occurred in Qingping Township, Mianzhu, Sichuan Province. Due to timely warning and rapid transfer, more than 5,000 people in this township successfully avoided danger. On June 5, 2011, Wangmo, Guizhou Province caused a geological disaster of mountain torrents due to a torrential rain. Because it was the Dragon Boat Festival holiday and it coincided with the night, it was extremely difficult to prevent it. However, after the early warning was issued, the local government took emergency measures in time and successfully transferred more than 45,000 people. Facts have proved that in the face of extremely destructive geological disasters, it is the most effective preventive measure to transfer refuge in advance.
　　"After receiving the early warning, the public in the earthquake zone should cooperate with the local government to transfer and avoid unnecessary confusion caused by panic." Zhang Guoping said.

　　(Source: China Meteorological News August 8, 2014 Third Edition Author: Liu Zhao Editor: Su Yujun)