It’s the Silicon Valley today with the choking smell of smoke, the yellow sky, the visible smoke and the pale sun. 2020 is really a year of natural and man-made disasters. California, which has suffered the most serious new epidemic in the United States, has fallen into the most serious mountain fire disaster. < / P > < p > this kind of scene appears almost every year, which means that California has entered the annual wildfire season. However, this year’s wildfires came earlier than usual. Affected by the continuous high temperature, thunder and lightning, dry hot and strong wind in the past week, large-scale wildfires broke out all over Northern California. As of Wednesday morning, at least 30 wildfires have been burning simultaneously near the San Francisco Bay area, in the northern, Eastern and central mountainous areas, with an area of more than 58600 hectares. The direct cause of the mountain fire is thunderstorm. The bay area originally belongs to the Mediterranean climate, and there is very little thunderstorm and lightning in summer, but there is nothing impossible in 2020. In the past three days, more than 10000 lightning strikes have occurred in California, triggering more than 360 wildfires, according to official data. In addition to the San Francisco Bay area, Southern California is also suffering from wildfires. < / P > < p > as in previous years, California Governor John Newson announced a state of emergency in California yesterday to mobilize resources to deal with fires that broke out across California. In addition, Arizona, Nevada and Texas also provide fire rescue equipment to California. Although the firefighters tried their best to put out the fire, the wildfire was still not effectively controlled. Residents in parts of Napa and Solano County, a well-known wine producing area in the northern San Francisco Bay area, were asked to evacuate this morning because of the fire. More than 46000 acres (18600 hectares) have been burned. < / P > < p > at present, it is impossible to count the fire damage and casualties this year. Air pollution in the San Francisco Bay area has skyrocketed. In San Mateo County and Santa Clara County, where Silicon Valley is located, two wildfires were burning at the same time on both sides, with an area of more than 38000 hectares. The dry monsoon from the desert valley in the East and the strong sea breeze in the Pacific Ocean in the west make silicon valley a gathering place of smoke and dust. < / P > < p > according to the monitoring data of the U.S. Environmental Protection Agency, except for a few Pacific coast areas, the air quality index of San Francisco Bay area has generally exceeded the “unhealthy level” of 150, and the mountain view city area where Google headquarters is located is approaching the “very unhealthy” level of 250, close to the air quality during the camp fire wildfire in 2018. The air quality index of EPA is different from PM2.5 index, which is a composite index of many pollutants. < p > < p > the SCU lighting wildfire in the eastern mountain area of Santa Clara County has an area of more than 34000 hectares. On the one hand, it is high temperature and dry; on the other hand, it is dry, hot and windy, with withered and yellow vegetation everywhere. In addition, the rugged terrain, firefighters’ fire fighting work has been greatly affected, so they can only send out aircraft to spray fire extinguishing agent. After a day of fighting, the fire is now under control of only 5%. < p > < p > wildfires and earthquakes are the two major disasters in California. There are thousands of wildfires in California every year. But in the past few years, the number of California wildfires has become more frequent and the impact has become more and more serious. So far, California has 6754 wildfires this year, far more than 4007 in the same period last year. Last year, the total number of wildfires was close to 7000. < p > < p > wildfires in California are also directly related to the climate here. The climate of California is divided into rainy season and dry season. Every year, the rainy season begins at the end of October, and December is the most rainy month, which lasts until the beginning of April of the next year. The hills and fields are full of green; the rest of the time is dry season, which is withered and yellow. In the half a year, the precipitation can be ignored, even the drizzle can not fall, and the air humidity is extremely low. Therefore, in autumn, when the vegetation is extremely dry, and catch up with the strong monsoon from the desert area, once the wildfire breaks out, it is very easy to get out of control. Climatologists believe that in the past decade, California has experienced the worst drought in the past 1000 years. This has also led to more frequent wildfires in California in the past few years, and the damage has become more and more serious. Of the 20 most serious mountain fires in California history, 14 occurred in the past 12 years; among them, the camp fire in Northern California in 2018 directly killed 86 people and damaged 18000 houses.