(a) The powers and duties of the City Manager shall consist of the following:
(1) The City Manager, through the Coordinator of Emergency Service, shall maintain general supervision over the planning and administration for the emergency service organization and the execution of the emergency service and disaster plans. He shall coordinate the emergency service activities and make assignments of emergency service duties and forces in order to meet situations not normally confronted by such forces.
(2) The City Manager may take all necessary action to conduct tests of the emergency service and natural disaster plans.
(3) When a state of emergency has been declared, the City Manager shall assemble and utilize emergency service forces and prescribe the manner and conditions of their use.
(4) The City Manager shall designate a line of succession among his department heads to carry out the powers and duties of this subsection in the event of his absence or inability to serve.
(b) The City Manager is hereby authorized to exercise the powers granted to the Mayor in Section 236.03, either in the absence or inability to serve of the Mayor and the Vice-Mayor or where delay in the exercise of such powers would be contrary to the public interest.