For the purpose of this subchapter the following definitions shall apply unless the context clearly indicates or requires a different meaning.
      (1)   A riot or unlawful assembly characterized by the use of actual force or violence or any threat to use force if accompanied by immediate power to execute by three or more persons acting
together without authority to law; or
      (2)  Any natural disaster or man-made calamity, including flood, conflagration, cyclone, tornado, earthquake, or explosion within the corporate limits of the village 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 health, safety, and welfare.
   CURFEW.  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 village, except officials of any governmental unit and persons officially designated to duty with reference to said civil emergency.
('79 Code, § 1912(1))