California is burning! Wildfires have spread(扩散) across the US since October 23rd and smoke has filled its skies.
The fires have got lots of people's life into trouble. Take the Kincade Fire in northern California for example. It forced 200,000 people to move away within one week. The state's largest power company(电力公司) cut power to about 206,000 homes in order to stop more fires from breaking out, Columbia Broadcasting System (CBS) News reported.
California has seen man wildfires in recent years. Nine of the ten biggest fires have happened since 2000, including five since 2010, according to The New York Times.
Why is this? California has the perfect wildfire conditions, Park Williams, a US climate expert, told The New York Times. It has dry air and high temperatures from spring through late fall. At the same time, seasonal winds blow across the state every year, causing the wildfires to spread quickly and last for weeks.
Global (全球的) warming has also made the fires worse in recent years. It has dried out the state's trees and other plant life, causing them to burn more easily.
__________ Burning campfires and cigarette butts ( 烟头 ) or other human activities can all easily cause wildfires. For example, one fire started last year when a car got an accident. The car's oil tank was hit broken, starting a fire.
Lightning strikes (雷击) and volcanic eruptions (火山爆发) can also cause wildfires. However, humans have caused 90 percent of California's wildfires, according to the US National Park Service.
