The major meteorological disasters in 2007 included drought, storm and flood, geological disasters, thunder and lightning, gale, hailstorm, violent temperature fall, continuous cloudy and rainy weather, fog, and plant diseases and insect pests caused by climate reasons. 104.74 million people-time suffered from, 226 people died from and 42 people were missing as a result of meteorological disasters and their derivative hazards throughout the Province. Moreover, 673,811 houses got damaged, 6.6 million hectares of crops recorded 10% reduction in yields, 2.9768 million hectares of crops recorded 30% reduction in yields, and 450,000 hectares of crops recorded 70% reduction in yields. Such disasters caused direct economic loss of 16.797 billion yuan, and direct economic loss of 9.571 billion yuan in agriculture. Among all meteorological disasters, storms caused the most severe damage. 36.9341 million people-time suffered from, 151 people died from and 37 people were missing as a result of storms together with floods throughout the Province. Moreover, 424,610 houses got damaged, 1.188 million hectares of crops recorded 10% reduction in yields, 688,900 hectares of crops recorded 30% reduction in yields, and 111,500 hectares of crops recorded 70% reduction in yields. Storms and floods caused direct economic loss of 10.071 billion yuan, and direct economic loss of 4.56 billion yuan in agriculture.
Drought. Drought conditions in Sichuan in 2007 lasted for a long period. Drought or dryness appeared successively from winter, spring, and summer to autumn. Wide areas suffered from drought in a repeated and lasting fashion, involving 163 counties and cities throughout the Province. Direct economic loss of 3.271 billion yuan arising from drought was reported in the Province. Winter dryness happened in 93 counties or cities, among which 52 were in the basin and 41 were situated in the plateau areas in northwestern Sichuan and mountainous areas in southwestern Sichuan. Affected areas included Mianyang, Suining, Ziyang, Neijiang, Zigong, Aba and Panzhihua and most part of Chengdu, Deyang, Guangyuan, Ganzi and Liangzhou and other individual places in the basin. Spring drought attacked 125 counties (or districts or cities) throughout the Province, among which 87 were in the basin. Spring drought covered most areas of the Province, while the northwestern and southern part of the basin was severely affected. Summer drought involved 105 counties (or districts or cities), among which 91 in the basin had summer drought lasting 20 to 64 days. And the middle, northwestern and southwestern part of the basin was seriously stricken. Rainfall of 60% to 80% less than that in the same period in history was recorded in the summer drought period in 2007. Autumn drought in 2007 in Sichuan was ordinary. Most places had moderate or minor drought and only individual places suffered from severe autumn drought. The autumn drought involved 94 counties (or districts or cities) throughout the Province, among which 76 were in the basin. Nanchong, most part of Mianyang and some part of Chengdu reported autumn drought conditions.
Storms and floods. In 2007, Sichuan’s rain was featured by local and violent rainstorms with uneven time and space distribution. Longchang County had the largest daily rainfall of up to 325.5 mm. On the 17th to 18th of June, the northeastern part of the basin had rainstorms of large scale. Local heavy thunderstorms and short-duration gales were reported in four counties, Xuanhan, Daxian County, Kaijiang and Dazhu in Dazhou City, with rainfall of 151.8 mm, 169.6 mm, 122.2 mm, and 101.4 mm respectively. That was Dazhou’s strongest local storm in history in the same period, causing 10 deaths and direct economic loss of 223 million yuan. On the 28th to 29th of June, Sichuan basin had the first local rainstorm and wide-spread thunderstorm. 17 counties (or cities) including Xingjing had heavy rainstorm. 6 counties (or cities) including Mingshan had rainstorm of over 100 mm rainfall. On the 2nd to 8th of July, part of the basin had constant rainstorm or heavy rainstorm. Strong precipitation was mainly in the northeastern part of the basin. Precipitation in this period was violent and long-lasting with wide-spread adverse effects. This precipitation involved 43 counties, cities or districts, and caused 26 deaths. 315,500 people were transferred, and direct economic loss of 3.036 billion yuan was reported. On the 8th to 10th of July, Neijiang, in the south of the Sichuan basin had rainstorm and heavy rainstorm. 6 counties (cities or distrcits) including Neijiang had rainstorm and 4 counties (cities or districts) including Nanxi had heavy rainstorm. The center of the strongest rainfall appeared in Longchang County, Neijiang City, with the largest daily rainfall of 325.5 mm, a new record high, while the largest daily rainfall of Hujia Town in Longchang County reached up to 366.6 mm. This precipitation caused 20 deaths and direct economic loss of 1.59 billion yuan. 10,000 people were transferred. On the 15th till the morning of the 20th of July, the basin had heavy rain and storms. Strong precipitation was mainly in 5 cities including Bazhong, causing 11 deaths and direct economic loss of 1.13 billion yuan. 80,000 people were transferred. On the 27th to 29th of July, Sichuan basin had rainstorm and heavy rainstorm from the west to the east and the south. Heavy rainfall was mainly in Mianyang. 31 counties (or cities) had rainstorm and 11 counties (or cities) had heavy rainstorm. The largest daily rainfall, 244.2 mm, appeared in the urban districts of Luojiang County, Deyang City. This precipitation struck 250 villages and towns of 17 counties (cities or districts) and 514,000 people, and caused direct economic loss of 164 million yuan. On the 24th to 25th of August, 11 counties or cities including Yibin and Ya’an had rainstorm and heavy rainstorm, attacking 106 villages and towns. 233,000 people were afflicted to different degrees and direct economic loss of 97.93 million yuan was reported.
Geological disasters. Violent precipitation in 2007 gave rise to many cases of geological disasters. There was a significant rise in the death toll compared with 2006. These disasters caused 56 deaths and 4 people were missing. The disasters also brought about direct economic loss of 314 million yuan and direct economic loss of 182 million yuan in agriculture. On May 20, short-duration violent precipitation in Leibo County led to floods and mud and rock flow of about 16,000 square meters. 9 civilian houses in this county were seriously damaged, among which 3 houses were totally washed away. 19 households of over 60 people were attacked and 10 people died in this accident. On May 24, heavy rainstorm in Jiulong County triggered fierce mud and rock flow. An area of 1,500 hectares was affected and 16,200 people were stricken. 12 people died and 6,700 people were transferred and resettled. Direct economic loss of 92 million yuan was reported. On June 6, Tianjiu Village in Pisha Town, Ningnan County had grave mud and rock flow, causing 5 deaths and direct economic loss of over 4 million yuan. On August 10, there was sudden heavy rainstorm at Yangjiagou of Caoke Village in Shimian County, Ya’an City. As a result, mud and rock flow struck the construction site of the Tianwanhe Dafa Hydro Electricity Power Station at Caoke Village, causing 10 deaths and 2 people were missing.
Gales and hailstorms. Local convective weather was frequent in 2007. Violent storms brought calamity to agricultural production and people’ life. Gales and hailstorms caused 19 deaths and 1 person was missing. Direct economic loss amounted to 2.207 billion yuan and direct economic loss in agriculture reached 1.222 billion yuan. On April 14, Meishan and other cities had severe gales and hailstorms, with winds of force 4 to 6 in general and in some places up to 9 to 10. This incident affected 10 cities, 27 counties (or cities or districts), 133 villages and towns, and 1.758 million people. 123,000 people were transferred and resettled. Direct economic loss of 380 million yuan was reported, 320 million yuan among which was in agriculture. On April 16 to 17, 17 counties and cities including Mianyang and Guangyuan had gales of force over 7. At 1:00 am on April 17, the highest instantaneous wind speed in Xichong County reached 31.6 meter/second, an unprecedented occasion since meteorological records were established in Nanchong City weather station. It was also the utmost value of wind force rarely seen in Sichuan basin. Hailstorm struck some places and Guang’an and Yuechi had rainstorms.
Thunder and lightning. A total of 968,485 occasions of lightning storms were recorded in Sichuan in 2007, and 39,630 were positive lightning and 928,855 were negative lightning. 266 days out of the year had thunder and lightning. Thunder disasters were counted 277, resulting in 47 deaths, the most death toll in all meteorological disasters. On June 7, thunder struck Qiaodi Village, Xichang City and caused 2 deaths and 9 people were injured. On July 16, Shenguo Village in Yuexi County, Liangshan Prefecture had thunder bolts. 3 people died at the spot and 9 others got injuries of different severity. On August 8, Datian Town in Renhe District, Panzhihua City had thunderstorms, resulting in 2 deaths and 6 were lightly injured.
Violent temperature fall. On the 1st to 3rd of April, the Sichuan basin had the sharpest temperature fall in Spring in the last 50 years. The daily temperature drop reached above 10℃ in general and the largest temperature drop amounted to 15.4℃. Accompanying sharp temperature drops were winds of force above 7 in some places. Xuanhan, Daxian County, Kaijiang, Nanjiang and Guang’an had also serious hailstorm. On the 6th to 9th of October, Sichuan basin had the first violent temperature fall since autumn began. The highest temperature in the basin dropped by 12 to 17℃ in general, while Langzhong had the largest drop of 18℃. This temperature fall was regarded as the most intense in the same period since 2000.
Continuous autumn rain. At the end of summer and the beginning of autumn (from August 23 to September 13), most part of Sichuan had long-duration rainy weather with low temperature and little sunshine. Such weather involved wide areas and lasted for a long period with many rainy days, low temperature and inadequate sunshine. As a result, late-mature rice in mountainous areas was insufficiently grain-filled and grain weight was thus reduced. Moreover, stigma exsertion rate was lower than the average year, the ratio of blighted grain increased, and false smut was prevalent. Corns that had matured remained in the fields and became rotted. The ripening of late-sowed rice in the middle of the basin was postponed and harvest was affected. Flowering and pollination of most of the ratoon rice was restrained, resulting in increased ratio of blighted grain. Some ratoon rice grew slowly and only eared at a rather later period. Constant rainy weather also had influence on the sowing progress of late-season crops. Crops that had been sowed were stunted and underdeveloped. In some places, rotted seeds, missing and withered seedlings were prevalent.
Heavy fog. Heavy fog was frequent in 2007 in the basin. Especially in December, the continuous heavy fog in most places of the basin had significant adverse effect on transportation, environment and people’ life. Sichuan Provincial Observatory released orange alerts for heavy fog in Sichuan basin in the 19, 21 and 22 of December. Chengdu Observatory issued red alerts for heavy fog in the 21 and 22 of December. As indicated by the data of the satellite FYID that passed Sichuan at 07:33 am on December 22, a total area of 26,971.84 square kilometers was covered by fog in the Sichuan basin, while Chengdu had an area of 2,495 square kilometers covered by fog.
Rampant rice planthoppers. The occurrence of rice planthopper hazards, their reproduction and migration has close connection with weather conditions. There were outbreaks of rice planthopper hazards in Guangxi and Yunnan in 2007, when the population of rice planthoppers that migrated into the southeast of the basin was remarkably more than the average year. What worsened the situation was that the Sichuan basin, especially south Sichuan and east Sichuan had large rainfalls from June to August and that there were frequent occurrences of weather conditions facilitating the migration and evolution of rice planthoppers. That resulted in the landing of a large population of the insects and their rapid reproduction. In the mid summer, rice planthoppers in Sichuan rice-growing areas became rampant, posing extreme threats to the grain security in the province. The provincial government started up the contingency program for severe disasters of hazardous insects. Up till August 16, altogether 137 counties (cities or districts) in 20 cities (or prefectures) suffered from rice planthopper destruction, and accumulatively 5.85 million mu of land was affected. Up till August 16, 18.8838 million mu-time of land was involved in the control of and treatment against rice planthoppers. The area of withered rice plants arising from rice planthopper destruction amounted to 18,900 mu, representing 0.06% of the total rice-growing land area.
The weather conditions in 2007 had both favorable and unfavorable effects on agricultural production. The climate conditions for agriculture were ordinary in 2007. In the seasons for agricultural production, the weather conditions in different parts were rather complex. Most places in the basin had an extraordinary warm and dry winter. After the super-grand autumn drought in 2006, the middle, northwest and south of the basin was once against attacked by spring and summer drought. The northeast and south of the basin suffered from floods, resulting in significant losses. Autumn long-lasting rain had considerably adverse effects on late-autumn production and autumn sowing. Regions that were irrigated by water conservancy projects in the west of the basin matched well with the light, warmth and rain conditions of the Panxi region. Harvests in spring, therefore, were steady and even increased, making great contribution to the gross output of grain in the province.