Natural phenomena are physical events which are generally separated into categories such as atmospheric, geologic, and hydrologic phenomena, as well as other categories and sub-categories. Well-known examples of natural phenomena include hurricanes, earthquakes, floods. Less common examples include debris flows, waterspouts, and insect plagues. Natural phenomena are simply events; there is no implication about an event’s relation to humans. The concept includes events with potentially minimal immediate risk to humans such as fog or a solar eclipse. Defining individual phenomena can be tricky, because a single phenomena may trigger several different natural phenomena. For example, a storm may trigger flash flooding, strong winds, fires, hail, or other events.