Wis. Stat. § 83.09

Whenever a flood or other casualty renders any county trunk highway dangerous for travel, the town chairperson may immediately close it and notify the county highway commissioner thereof, and the commissioner shall promptly make repairs necessary to render the highway safe for travel. If sufficient funds are not available in the county maintenance fund, the commissioner may, with the consent of the chairperson of the county board or of the county highway committee, make the necessary repairs, and the cost thereof shall be paid as soon as funds are available.