Coho salmon are in the river at this time. New fish should enter the river whenever some rain falls. To pursue the coho, try a sink-tip line and a seven- or eight-weight rod. Cast to water similar to what you'd fish for steelhead, except maybe a notch slower. Avoid fish that are jumping and rolling; while these highly visible fish can get anglers excited, they are poor biters.
A good local pattern is a Bumblebee. It's tied on a size 6-8 hook. The tail is pearl KrystalFlash. The body is a short green chenille tag (like for a Green Butt Skunk) followed by yellow and brown variegated chenille. Palmer with grizzly hackle. That's it. Nothing fancy, but locals swear by it. Cast your fly down-and-across and let it swing. At the end of the swing, strip it back--fast.
The river has many chinook, and these are mostly dark and in spawning mode by now. Avoid walking through redds (gravel scraped clean) and don't think it's great sport to snag dark chinook with your flies.
Mid- to late-October, a second run of coho enters the Kalama. The first run is from the lower hatchery. These fish do their ocean feeding south of the Columbia River. The second run is from the upper hatchery, near the falls; they do their ocean stint north of the Columbia.
This second run enters the Kalama in late October and has to travel a few more miles upstream to reach the concrete tanks in which they were raised.
So later this month, coho fishing should get a second wind. These fish will be more spread out than the first run because they have to travel farther.
The coho hot spots can be crowded, so get there early in the day (like, pre-dawn). If you find yourself surrounded by leaping, rolling coho, move on. They rarely bite when they're acting like that. Most of the coho action is in the lower five miles.
If you're looking for steelhead, tie on a size 6 or 8 black Woolly Worm with a red tail or an After Dinner Mint. The Kalama has a high south bank, so the river is shaded much of the day and fishing is not restricted to just the early morning and evening hours.
For more on October tactics and flies, see the Rivers in General forecast