>>490132>lake lillianAbout 5 minutes searching around Google Maps independently, finding the same lake, and then seeing your post and doing a Google Images search appears to confirm this to be it.
https://www.google.com/maps/@47.8598081,-123.392057,2115m/data=!3m1!1e3There could certainly be other possibilities, and since the satellite image Google uses is in the early season, it's hard to confirm the grasses and exact shape of the water, but this looks pretty close to it.
