Warm weather means giving Firehole River resident salmonids a break from the rigors of being hooked and played in warming waters. Try the nearby Madison or Gibbon Rivers where PMDs, yellow sallies, and afternoon caddis activity are interesting trout. Big salmonflies have pretty much left the Gallatin River within the park, but terrestrial insect populations are building and caddis are always active during PMs. Slough Creek and the Lamar River are shaping up with PMD, evening brown drake, and caddis activity interesting trout. Fall River Basin streams are reducing to base level flows, terrestrial insect populations are building but mosquitoes are still the most numerous insect.