Floods, hurricanes, tornadoes, earthquakes, and wildfires are some of the most common natural disasters that occur. Floods happen when rivers overflow their banks or heavy rainfall overwhelms drainage systems. Hurricanes form over warm ocean waters and bring high winds, heavy rain, and storm surges. Tornadoes are rotating columns of air that extend from thunderstorms to the ground. Earthquakes occur when two blocks of the earth suddenly slip past one another along a fault line. Wildfires can start naturally from lightning strikes or volcanoes, but some are caused by human activities like arson or negligence.