Is ham radio used by any government department for disaster management and if yes then how?

Answer 1

Most emergency agencies are quite happy when hams volunteer to communicate for them.

A good example is in the destruction of the World Trade Center where the power and phone lines were taken out. The police could not contact fire, or even their own officers, and the fire departments could not contact the police, or their own fire engines. Hams, or Amateur Radio Operators, came to the scene by the hundreds - each totally a volunteer using their own emergency rigs. The rigs consist of at least a handheld VHF or UHF two-way radio and a bunch of batteries for it connected and kept in a back pack or belt pack.

There would be hams on scene, and other hams at the police stations, the fire stations, the New York City disaster teams, and so forth. These hams would pass on information by radio that the emergency responders could not.

This is very typical. Hams respond to many disasters to provide all sorts of communications for the local emergency responders. Some, like in the World Trade Center disaster, travelled, using their own money, from other states, even from far away states, just to help the emergency responders. This same response occurs after hurricanes, tornadoes, volcanic eruptions (Mt St Helens in Washington state for example), search and rescue situations, and so forth.