S.D. Codified Laws § 7-21-21
In the event of an epidemic or disease or act of God, disaster, catastrophe, or accident, which results in damage to or destruction of any of the works, roads, buildings, or property of the county or any of its institutions or agencies, and the results of which have not been anticipated in the annual budget adopted for the fiscal year in which the same occur or take place, and which require the incurring of liabilities or expenditures of funds in connection with the suppression of the epidemic or disease, restoration of works, roads, buildings or property, or removing the menace above referred to, and restricted to causes where no other funds have been provided or appropriated therefor, the board may without further notice or hearing adopt a supplemental budget making and providing for an appropriation for the purpose and object, and for an amount deemed necessary, and may then incur liabilities or expend funds for such purpose, but not to exceed in the aggregate the amount specified in such supplemental budget.
SDCL 7-21-21