A process or event in the physical environment that is not caused by humans, is usually not entirely predictable, but can injure or kill people and damage property. Examples include natural processes such as volcanoes, earthquakes, violent storms (including hurricanes and tornadoes), river flooding, storm surges, droughts, avalanches and landslides, and sea level rise. Three trends have increased the problems of coping with natural hazards in recent decades—population increase, human impacts on environmental systems, and technological hazards. The net effect of these changes, particularly in recent decades, has been an increase in exposure to many hazards, and increased potential for catastrophic losses. Also known as environmental hazard. See also International Decade for Natural Disaster Reduction.