Slough Creek Fishing Report: August Conditions & Fly Patterns for Yellowstone

Question
I plan to visit Slough Creek in Yellowstone Park in mid August for the first time. What are water conditions likely to be, and what patterns do you recommend?

Answer
With the past weeks being relatively hot, grasses have dried out significantly making it ideal for terrestrials. I'd suggest small hoppers (sizes 8-14), black and cinnamon winged ants (sizes 14-20), and black foam beetles (sizes 12-16). Other tried and true patterns are black and olive Flash-a-Buggers stipped slow along bank edges, and a parachute adams dry (sizes 12-16) trailed by a #18 PT flashback.

Water levels will be medium to low, wet wading is fine. Have insect repellent handy. Fish buggers early morning and late evening, terrestrial dries from 10am-7pm or so. Good luck.

Mike