S.D. Codified Laws § 6-6-1
Whenever, due to an emergency resulting from the effects of enemy attack, or the anticipated effects of a threatened enemy attack, it becomes imprudent, inexpedient, or impossible to conduct the affairs of local government at the regular or usual place or places thereof, the governing body of each political subdivision of this state may meet at any place within or without the territorial limits of such political subdivision on the call of the presiding officer or any two members of such governing body, and shall proceed to establish and designate by ordinance, resolution, or other manner, alternate, or substitute sites or places as the emergency temporary location, or locations, of government where all, or any part, of the public business may be transacted and conducted during the emergency situation. Such sites or places may be within or without the territorial limits of such political subdivision and may be within or without this state.
SDCL 6-6-1