I've skied public park in august a few times and really enjoyed it. Depending on when in the month specifically, the snow cover could vary greatly. Either way, you'll be up on Palmer exclusively. The nice thing about august is that the weather is dependable, and the bloody crowds are usually gone (save a few racers and some others). I'm not sure what the snow pack is doing in oregon (practically disintegrating on WA volcanoes though), but there may be a couple jumps, and rails/boxes to boot. A friend of mine lived there for a couple years, and if i recall correctly, the public park reclaims some of the lane space that was used for high cascade. I may be dead wrong though.
Regardless, I'd say go for it. It won't be pristine, but it can be good times.
