Whenever the commissioner determines that an extraordinary situation exists anywhere in this state the commissioner may, by proclamation, authorize banks located in the affected area or areas to close any or all of their offices. The office or offices so closed shall remain closed until the commissioner proclaims that the extraordinary situation has ended or until such earlier time as the officers of the bank determine that one or more closed offices should reopen and in either event for

such further time thereafter as may reasonably be required to reopen.