What forms of communication have been used during recent disasters e.g Hurricane Katrina, the Asian Tsunami?

Many different techniques of communication was used during Hurricane Katrina and Asian Tsunami. Ham operators were one of the way that helped to communicate in hurricane katrina using voice, computers, televisions and Morse codes. Some hams bounce their signals off the upper regions of the atmosphere, so they can talk with hams on the other side of the world; others use satellites. Many use short-range, handheld radios that fit in their pockets. Cellphones were a vital aid in communicating to get help. Families were able to text or call friends or other relatives in different parts of the world to get help. If they were to try to call 911 the system would probably be overloaded. There are still many other sorts of communication used in now a days natural disasters.