The document defines and describes different types of natural disasters:
1. Natural disasters are occurrences that cause damage, loss of life, and deterioration of health on a scale that requires outside assistance. They include meteorological events like cyclones and tornadoes, topographical events like earthquakes and volcanic eruptions, and environmental events. 
2. Some of the worst natural disasters in history include the 1970 Bhola cyclone that killed 500,000 people, the 1960 Chile earthquake with a magnitude of 9.5 that killed 6,000, and the 2004 Indian Ocean tsunami that caused 230,210-280,000 deaths.
3. Unusual natural disasters mentioned include firenadoes, which are