Wis. Stat. § 220.30: Closing in emergencies.

No liability shall be incurred by a bank because the bank is closed during an emergency. If a bank closes during an emergency, the closing shall be noted in the minutes of the next meeting of the bank’s board of directors. A bank may not declare in default for nonpayment any obligation which became due while the bank was closed during the emergency if timely payment on the obligation was tendered but not accepted because the bank was closed.