The difference between Disasters, Catastrophes and Natural Hazards.

A natural hazard is a process that may endanger human life but may not. They can be fatal if humans are in the path but otherwise are just natural occurrences of the earth and its abilities.
Disasters and Catastrophes are a bit different. They most likely will always have fatalities. A catastrophe is a huge disaster such as hurricane Katrina that  cause massive damage to areas and cause many deaths requiring a lot of money to be spent repairing what has been destroyed. Finally we have disasters. Hazardous events that occur for certain amounts and time and span in specific places. Usually a declared state of emergency follows a disaster, along with requested international assistance which is not always required.