Wyo. Stat. § 21-3-109: When vacancy on board deemed to have occurred.

(a) A vacancy shall have occurred in the membership of any board of trustees of any school district if any member:

(i) Dies;

(ii) Resigns;

(iii) Becomes a nonresident of the school district; or

(iv) Becomes a nonresident of the trustee residence area from which elected in those districts subdivided into trustee residence areas.