RCW 42.14.040: County commissioners.

In the event that a catastrophic incident reduces the number of county commissioners of any county, then those commissioners available for duty shall have full authority to act in all matters as a board of county commissioners. In the event no county commissioner is available for duty, then those elected county officials, except for the members of the county board of education, as are available for duty shall jointly act as the board of county commissioners and shall possess by majority vote the full authority of the board of county commissioners.