Source could be getting close. Be sure to hike ALL of it before dropping in on that thing. The gauge is below the confluence with Jasper Creek, which tends to have more water then the N fork on the front end of the season. On the tail end more of the water on the gauge tends to come from the North or source side.
AA is overrated. It's pretty, but it is not creek boating, and you better have a fast boat if you think you're going to surf something in there. It is fast and eddy-less at higher flows, and while not overly challenging, it is not a good intermediate run because if you swim your boat is going to run USB without you.
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