(1) By an affirmative vote of a majority of the city council pursuant to the charter, art. V, § 1.

(2) By serving the city clerk notice in writing and signed by a majority of the city council. The clerk shall immediately give verbal or written notice to each member of the council, stating the date and hour of the meeting and the purpose for which such meeting is called, and no other business shall be enacted at that meeting. The clerk in the notice of a special meeting initiated in this manner shall allow at least 24 hours to elapse between the call of the meeting and the date and hour of the meeting.

(3) By verbal notice to the city clerk or the city manager by a majority of the city council whenever an emergency exists which requires immediate action by the council. The clerk shall immediately attempt to give notice to each member of the council stating the hour of the meeting and the purpose for which such meeting is called, and no other business shall be enacted at that meeting. If, after reasonable diligence, it is impossible to give notice to each councilmember, such failure shall not affect the legality of the meeting.