This is a violent, sudden and destructive change, whether it is on
the quality of the surface of the earth, or on the distribution or
movement of water in the surface or atmosphere.
A flood is an overflow of water that 'submerges' land. The EU Flood
Directive defines a flood as a temporary covering by water of land which
is usually not covered by water.In the sense of 'flowing water', the word
may also be applied to the inflow of the tides. Flooding may result from
the volume of water within a body of water, such as a river or a lake, which
overflows causing the result that some of the water escapes its usual
boundaries. While the size of a lake or other body of water will vary with
seasonal changes in precipitation and snow melt, it is not a significant
flood unless the water covers land used by the man like a village, city or other
inhabited area, roads, expanses of farmland, etc.
The Limpopo River during the 2000 Mozambique flood
A limnic eruption occurs when a gas, usually carbon dioxide , suddenly erupts from
deep lake water, posing the threat of suffocating wildlife, livestock and
humans. Such an eruption may also cause tsunamis in the lake as the rising
gas displaces water. Scientists believe that landslides, volcanic activity, or
explosions can trigger such an eruption. To date, only two limnic eruptions
have been observed and recorded. In 1984, in Cameroon, a limnic eruption in
Lake Monoun caused the deaths of 37 nearby residents, and at nearby Lake Nyos
in 1986 a much larger eruption killed between 1,700 and 1,800 people by asphyxiation.
A tsunami, also known as a seismic sea wave or a tidal wave, is a series of
waves in a water body caused by the displacement of a large volume of water,
generally in an ocean or a large lake. Tsunamis can be caused by undersea
earthquakes such as the 2004 Boxing Day tsunami, or by landslides such as
the one in 1958 at Lituya Bay, Alaska, or by volcanic eruptions such as the
ancient eruption of Santorini. On March 11, 2011, a tsunami occurred near
Fukushima, Japan and spread through the Pacific.