A natural disaster is a major adverse event, which can cause loss of life or property damage, and typically leaves some economic damage. There are many types of natural disasters: avalanches, earthquakes, volcanic eruptions, floods, tsunamis, blizzards, droughts, hailstorms, tornadoes, wildfires. If an adverse event occurs in an area without vulnerable population, it will not have such disastrous consequences, as if it occurs in area of vulnerable population as in San Francisco.
One of the biggest natural disasters, which appear mostly in mountainous area, is avalanche. An avalanche occurs when a mass of snow falls down from the mountainside. That is because new snow, which is not wet, falls on a more heavy snow layer. This causes that the layer of snow is too big and it start to slide down toward the base of mountain. One of the biggest avalanches in world history was in Italian - Austrian Alps. During World War II, Italy and Austria had military bases in the Alps – soon finding that bombs and enemy fire weren't the only threats. Heavy snow instigated a series of avalanches in the Tyrol region causing the deaths of 10,000 soldiers on what became known as White Friday 1916. Of course one of the natural disasters is an earthquake (also known as a quake, tremor or temblor). Earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The largest earthquake, which killed 1655 people, thousand of them was injured and millions were left homeless, was in Chile in 1960. Quake, which magnitude was 9.5, trigged a tsunami, which killed 61 people in Hawaii, 138 in Japan and 32 in the Philippines also suffered $550 million USD in damage.
Volcanic eruptions are the Earth's most powerful and destructive forces. An eruption begins when pressure on a magma chamber forces magma up through the volcano's vents. The explosion of Mount Tambora, which is still active, is one of the tallest peaks in the Indonesian