Wash. Rev. Code § 32.16.040
A quorum at any regular or special or adjourned meeting of the board of trustees shall consist of not less than five of whom the chief executive officer shall be one, except when he or she is prevented from attending by sickness or other unavoidable detention, when he or she may be represented in forming a quorum by such other officer as the board may designate; but less than a quorum shall have power to adjourn from time to time until the next regular meeting. However, a savings bank may adopt procedures which provide that, in the event of a national emergency, any trustee may act on behalf of the board to continue the operations of the savings bank. For purposes of this subsection, a national emergency is an emergency declared by the president of the United States or the person performing the president's functions, or a war, or natural disaster.
Regular meetings of the board of trustees shall be held as established from time to time by the board, not less than six times during each year.
RCW 32.16.040