natural disasters

While avalanches are sudden, the warning signs are almost always numerous. In 90% of incidents involving avalanches, snow slides are caused by the victim or any member of the victim group. Avalanches kill more than 150 people worldwide each year. Most of the victims are people who go by snowmobile or snowboarders or skiers.

 

Many avalanches are small slides dry powder snow that moves a formless mass. These "scrubs" represent a tiny fraction of the death and destruction that involve older siblings and more organized. The disastrous avalanches occur when huge snowpack emerge from the mountainside and shatter like broken glass as they rush down the hill. These moving masses can reach a speed of 130 kilometers per hour in about five seconds. Victims caught in these events can almost never escape. Avalanches are most common during and after the 24 hours following the storms that discharge 30 inches or more of fresh snow. This rapid stacking the snow overload which causes a weak layer under the big slab fractures. Layers are an archive of winter weather: heavy snow, drought, rain, snow and heavy frosts. The manner in which the layers adhere determine the ease with which weakens one and cause a slippage.

A terremoto1 (Latin: terra "earth" and motus "movement"), also called earthquake or earthquake (Greek σεισμός "shaking" and "earthquake") is a phenomenon of sudden shock and passing of the crust produced by the release of energy stored in the form of seismic waves. The most common are caused by the rupture of geological faults. They can also occur for other reasons such as, friction on the edge of tectonic plates, volcanic processes or even be produced by man when testing underground nuclear detonations.

The point of origin of an earthquake is called the hypocenter. The epicenter is the point on the Earth's surface directly above the hypocenter. Depending on its intensity and origin, an earthquake can cause displacement of the earth's crust, landslides, tsunamis or volcanic activity. For the measurement of the energy released by an earthquake different scales are used among which the Richter scale is the most known and used in the media

A flood is the occupation by water areas that are usually free of this, either by overflowing rivers and streams by rainfall or snowmelt, or seas by rising tides above the usual level or avalanches caused by tsunamis.

The river floods are natural processes that have occurred periodically and have been the cause of the formation of the plains in river valleys, fertile lands traditionally developed agriculture in the valleys and riverbanks.

In coastal areas the sea attacks have served to shape and create coastal wetlands and lagoons and lakes that following its occupation atopic, have become vulnerable areas