The YA winner is: Jumped In, by Patrick Flores-Scott.
See the other winners here and the other shortlisted titles here. (Is it just me, or is it really, REALLY confusing that the early readers, middle grade, and YA finalists are all together on the same shortlist, but in different winning categories? Ag.)
Related: The 2013 Washington State Book Awards.
Related: The 2007 Washington State Book Awards.