RCW 36.32.100: Chair of board—Election, powers.

The board of county commissioners at their first session after the general election shall elect one of its number to preside at its meetings. He or she shall sign all documents requiring the signature of the board, and his or her signature as chair of the board shall be as legal and binding as if all members had affixed their names. In case the chair is absent at any meeting of the board, all documents requiring the signature of the board shall be signed by both members present.