If, in the event of an attack, or in the event of a state of extreme emergency, state of disaster or the existence of a local peril, local emergency or local disaster, any officer named in § 2.56.020(A) and (B) and any duly authorized deputy is unavailable, his or her emergency interim successor highest in rank in order of succession who is not unavailable shall, except for the power and duty to appoint emergency successors, exercise the powers and discharge the duties of such officer. An emergency interim successor shall exercise these powers and discharge these duties only until such time as the lawful incumbent officer or any duly authorized deputy or any emergency interim successor higher in rank in order of succession exercises or resumes the exercise of the powers and discharge of the duties of the office, or until, where an actual vacancy exists, a successor is appointed to fill such vacancy or is elected and qualified as provided by law.
(`78 Code, § 2.56.050.)