§ 657. Emergency fund. The board of supervisors shall have power to appropriate and set aside a fund for the purpose of paying in advance of audit expenditures of a sheriff in an emergency or catastrophe for services and expenses of special deputies and for the hiring of equipment and apparatus and the operator thereof. The board may authorize the sheriff to issue orders on the county treasurer for the payment thereof and may require a countersignature of the chairman of a designated committee of such board. It may further direct the rendering of an accounting of such expenditures with verified or certified vouchers attached and such other conditions and rules as the board may deem proper. The claimant and the sheriff shall be jointly and severally liable for any item of expenditure for other than a lawful county purpose disallowed upon a final audit to be recovered in an action brought by the board of supervisors in the name of the county.