Yep, the Bladder was in from mid-May to mid-June this year. We need above average snowpack in the Payette Drainage, favorable release timing out of Cascade or massive flow on the SF Payette (total flow on the Main Payette at Horseshoe Bend must exceed 10 grand), and the bladder must be partially deflated to pass the high flow. The wave doesn't form if the bladder is completely deflated. The shape of the wave was slightly different every time I surfed it this year because the air moves around in the bladder. Sometimes, at identical flow, it was sicko and other times it was flat and barely surfable.
All that adds up to being one of the least predictable, but most rewarding features I have been lucky enough to surf. Pray for snow.
"A river is more than an amenity, it is a treasure."
-Oliver Wendell Holmes writing for the majority in New Jersey v. New York