As used in this chapter:
   (a)   "Civil emergency" means:
      (1)   A riot or any civil disturbance, disorder or other occurrence that constitutes a clear and present danger to the health, safety and property of the residents of the Municipality, or substantially impairs the functioning of the Municipal government and its ability to protect the lives and property of the people; or
      (2)   Any natural disaster or man-made calamity, or clear and present danger thereof, including, but not limited to, flood, conflagration, cyclone, tornado, earthquake or explosion within the corporate limits of the Municipality resulting in the death or injury of persons or the destruction of property to such an extent that extraordinary measures must be taken to protect the public peace, health, safety or welfare.
   (b)   "Curfew" means a prohibition against any person or persons walking, running, loitering, standing or motoring upon any alley, street, highway, public property or vacant premises within the corporate limits of the Municipality, excepting persons officially designated to perform duties with reference to such civil emergency.