The flows on the Callaghan are ones to watch.
Check out the
Rivers Page here and then select British Columbia.
For the Callaghan look for flows of 2.3 to around 2.8 meters on the Cheakamus Gauge. The Callaghan flows into the cheakamus and although they do drain different valleys it is the only indicator around for that drainage. Rain affects the run alot as does sunshine and hot temps. So watch the weather. Once your up there go to the cheakamus takeout and you can walk down to the gauge station to see the staff gauge. There is a trail and a little off shoot to the right that will lead you to the staff gauge. This last weekend it was between 2.10 and 2.9 ... Really high levels for both the cheak and callaghan.
Ashlu I don't have expierence with but I believe it is high right now from what some locals said this last weekend. Check out the Soo and Cayoosh Creek too. The Nahatlatch should have plenty of water if not a little high but it would be fun but a bit out of the way. The Frog Wave is not in until Sept so don't worry about that, but the skook will be rockin in its place.
Take some photos and give us the feed back I would love to hear how the runs go.
James