Natural disasters are major events that can damage the land or threaten human lives. They include volcanic eruptions, earthquakes, cyclones, avalanches, floods, droughts, and forest fires. Volcanic eruptions occur when gas, ash, and molten rock burst from openings in the Earth's crust due to underground pressure. Earthquakes are caused by the movement of tectonic plates deep below the surface. Cyclones, hurricanes, typhoons, and tornadoes are powerful rotating storms with high winds that can destroy buildings and uproot trees.