The specific situation of Xiaogan flood disaster

Xiaogan City is one of the prefecture-level cities under the jurisdiction of Hubei Province. It now governs Xiaonan District, Yunmeng, Dawu and Xiaochang counties, and Hanchuan, Yingcheng and Anlu county-level cities. The existing land area is 89 10 square kilometers with a total population of 5.06 million.

Xiaogan city is located in the mid-latitude zone and belongs to the subtropical monsoon climate. There are four distinct seasons in the territory, with northerly winds prevailing in winter, southerly winds prevailing in summer, short-lived hot and cold in summer, and mild climate in spring, autumn and early summer for a long time. Abundant rainfall, with annual average precipitation1133.8mm; Sufficient light and heat, annual average sunshine hours 1, 996.7 hours, annual average temperature 16.0℃, accumulated temperature ≥ 10℃ 509 1.9℃, are beneficial to the development and growth of crops. It is a zone with good coordination of light, heat and water conditions in China. However, there are frequent rainstorms in early summer and rainy season, which are prone to floods, and high temperature evaporation in midsummer often leads to summer drought. Flood and drought have become the main natural disasters in this city.

In spring (March to mid-May), the temperature rises, the rain increases, the temperature changes, and there are often low temperature and rainy days. After the spring, the temperature rises rapidly and the rainfall increases obviously, which is beneficial to the development of spring sowing crops and the growth of wintering crops. Spring is also a season of frequent alternation of cold and warm air, with an average of 7 ~ 10 days, resulting in more sunny and rainy days from mid-March to mid-April, changeable wind direction and sudden rise and fall of temperature.

In early summer (from late May to mid-July), the temperature is suitable, there is plenty of rain, and there are many rainstorms in rainy season, so floods can occur.

In midsummer (from late July to August), the weather is hot and often dry. After the summer, the cold air in the north gradually weakened, and the warm air in the south gradually strengthened, and the weather changed from cold to hot, with an average temperature of 23 ~ 28℃, which was suitable for the normal growth of crops. The rainy season is from mid-June to mid-July, and there are often heavy or continuous heavy rains, which are easy to cause flash floods in the north and floods and floods in the south. After the Meiyu ended, it entered the hot summer, and the rainfall in the territory decreased obviously, the relative humidity decreased, the sunny days increased, and the temperature increased. The average daily temperature is above 28℃. At the end of July and the beginning of July, southerly winds of 3 ~ 4 grades can appear in about one third of a year, which has certain influence on flowering and pollination of mid-season rice. During this period, high temperature weather above 35℃ often occurs, and at the same time, there is little rain and large evaporation, which is prone to drought. However, in a few years, excessive precipitation or heavy rain caused local flooding.

In autumn (September-165438+1October), there are many sunny days, few rainy days, and sometimes it is cool in autumn. In autumn, the cold air forces in the north gradually strengthened and even controlled the whole territory. The cold and warm air confrontation area moved out of Xiaogan, and the rainy weather turned into sunny and hot weather, with less rainfall, more rainy days, more sunshine hours, large daily temperature difference, high temperature during the day and cool at night. It is called "crisp autumn" climate, which is conducive to the late growth of autumn crops and autumn harvest. However, in September of some years, there were long rainy days, which made the daily average temperature lower than 20℃, resulting in autumn cold.

Winter (65438+February ~ February) is cold with little rain (snow), and there is freezing injury at the end of winter. Winter has the seasonal characteristics of low temperature and less rainfall. The average temperature in various places is mostly below 3 degrees, and the overwintering crops basically stop growing. Generally speaking, strong cold waves often attack, and the minimum temperature can drop below MINUS 5 degrees, accompanied by rain and snow and northerly winds above 5 degrees, which freeze crops and affect people's lives. But there are also a few years that are relatively warm "warm winters".