An avalanche results from a large mass of snow and ice suddenly slipping from its position and moving rapidly down a slope.
Different terms are used around the world to refer to these fires, which may be caused by humans or natural forces like lightening, and which often cause a lot of damage. They may occur in forests, grasslands, or farming areas, and sometimes burn for days or weeks before being brought under control.
Floods are a common natural disaster, and can be caused by excessive rain, a break in the wall of a dam or levee, or by a change in sea level such as a tsunami.
Landslides can occur after heavy rain, if a retaining structure gives way, or if a weakness develops in the ground. They are called mudslides if the soil is saturated with water.